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A positive association between pubertal maturity as assessed by skeletal development, and specific cognitive abilities has recently been demonstrated in a cohort of adolescent girls. The current study explores the impact of chronological age and relative pubertal maturity on executive function within the same cohort. Relative maturity, determined by the difference between chronological age and skeletal age, establishes the criteria for enrolling participants into average, advanced, or delayed relative maturity subgroups. Performance is assessed using the Numerical Stroop test and analyzed across four conditions, each with varying task requirements related to inhibition and task switching. The effects of chronological age and relative maturity on executive functions are tested by a linear mixed model. Within the examined age-range (12-15 y), a more protracted development was found for inhibition as compared to switching. In line with the previous findings, the results reveal significant development in executive performance as a function of chronological age, and relative maturity also demonstrated significant effect on the development of executing functioning. The significant interaction effect between Chronological Age and Relative Maturity suggests that the degree of interplay between these factors varies across the examined age range. Specifically, relative maturity may have a more noticeable impact on EF functioning in middle adolescence compared to early adolescence., Competing Interests: Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

Life-history information is necessary for effective conservation, aquaculture development and broodstock management of fishing populations, especially for fish with significant economic exploitation. Aiming to characterise the life-history traits in relation to the environmental parameters of the long-whiskered catfish, Mystus aor, a commercially important species from Kaptai Lake, Bangladesh, different life-history data were analysed. The monthly condition factor (K) ranged from 1.15 to 1.41, and the relative condition factor (Kn) ranged from 0.14 to 0.25. The estimated relative fecundity was 18474-55504 eggs/per fish, and the maximal oocyte diameter was found in May (0.83 ± 0.11μm). The lengths at first sexual maturity (Lm) for male and female M. aor were 49.5 cm and 54.1 cm, respectively. The GSI was peaked in May for both males and females, and histological analysis also revealed the presence of yolk granules and several mature spermatids in April and May in both sexes. Analysis of environmental data over 40 years in the Kaptai lake ecosystem indicate the significant increase in the precipitation rate in spawning month which is highly correlated with the spawning season. The findings of the current study will serve as a baseline for the conservation and broodstock management in the Kaptai Lake of Bangladesh., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Noor et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Previous studies have suggested that adamts9 (a disintegrin and metalloprotease with thrombospondin type-1 motifs, member 9), an extracellular matrix (ECM) metalloprotease, participates in primordial germ cell (PGC) migration and is necessary for female fertility. In this study, we found that adamts9 knockout (KO) led to reduced body size, and female-to-male sex conversion in late juvenile or adult zebrafish; however, primary sex determination was not affected in early juveniles of adamts9 KO. Overfeeding and lowering the rearing density rescued growth defects in female adamts9 KO fish but did not rescue defects in ovarian development in adamts9 KO. Delayed PGC proliferation, significantly reduced number and size of Stage IB follicles (equivalent to primary follicles) in early juveniles of adamts9 KO, and arrested development at Stage IB follicles in mid- or late-juveniles of adamts9 KO are likely causes of female infertility and sex conversion. Via RNAseq, we found significant enrichment of differentially expressed genes involved in ECM organization during sexual maturation in ovaries of wildtype fish; and significant dysregulation of these genes in adamts9 KO ovaries. RNAseq analysis also showed enrichment of inflammatory transcriptomic signatures in adult ovaries of these adamts9 KO. Taken together, our results indicate that adamts9 is critical for development of primary ovarian follicles and maintenance of female sex, and loss of adamts9 leads to defects in ovarian follicle development, female infertility, and sex conversion in late juveniles and mature adults. These results show that the ECM and extracellular metalloproteases play major roles in maintaining ovarian follicle development in zebrafish., (© The Author(s) 2024. Published by Oxford University Press on behalf of Society for the Study of Reproduction. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Armed conflict and forced migration (ACFM) represent a set of extreme environments that are increasingly common for children and adolescents to experience. Adolescence may constitute a sensitive period (puberty and psychoneurological maturation) through which ACFM adversity leaves a lasting mark. Adolescence has become a focal point for analysis and intervention as it relates to the effects of early life adversity on puberty, linear growth, and mental health. Research in public health and psychological science suggests early life adversity (ELA) may accelerate puberty, heightening risks for mental health disorders. However, it is not well substantiated whether ACFM-derived adversities accelerate or delay relative pubertal timing. Secondly, ACFM provides salient context through which to probe the relationships between nutritional, psychosocial, and demographic changes and their respective impact on puberty and mental health. We conducted a narrative review which 1) examined constructions of early life adversity and their proposed influence on puberty 2) reviewed empirical findings (n = 29 studies, n = 36 samples) concerning effects of ACFM ELA on age at menarche and 3) discussed proposed relationships between early life adversity, puberty, and mental ill-health. Contrary to prior research, we found war-derived early life adversity was more consistently associated with pubertal delay than acceleration and may exert counterintuitive effects on mental health. We show that ELA cannot be operationalized in the same way across contexts and populations, especially in the presence of extreme forms of human stress and resilience. We further discuss the ethics of puberty research among conflict-affected youth., Competing Interests: Declaration of Competing Interest None., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Background: Evaluation of pubertal development is crucial in Endocrinology. The rise in telemedicine during COVID-19 has made conduct of physical examinations more challenging, especially for pubertal assessment. Previous studies on validity of pubertal self-staging versus clinical examination have yielded mixed results. This study aimed to determine validity and reliability of self-staging of puberty, with potential application during telemedicine visits. The present study is the first to assess pediatric self-rated pubertal staging during the pandemic., Methods: The study included patients aged 7-22 years referred to Pediatric Endocrinology for specialty care, including pubertal staging. At clinic check-in, patients received a packet with study description, an option to "opt in" or "opt out", sex-specific self-staging instructions, and Tanner (T) stage illustrations. Males received materials for pubic hair (PH) stages T1-T5; females received materials for PH and breast (BR) stages T1-T5. Patients who opted in had 10 minutes to select the image(s) that best matched their bodies, which they sealed in an envelope. This was followed by a clinic visit, where a board-certified pediatric endocrinologist conducted a physical examination, including breast staging (females), testicular size measurement (males), and pubic hair staging (both sexes). Pubertal stage Kappa statistics with 95% CI were calculated for each body part by sex, with Kappa ≥ 0.60 indicating significant agreement between self-assessment and physician assessment (0.40-0.60 moderate; 0.20-0.40 fair)., Results: Of 516 distributed packets, 243 self-assessments (125 females) were returned, with 81% (94 females/102 males) being complete (including pediatric endocrinologist staging). Mean age of participants was 12.8 years. Mean BMI was 22.2 kg/m² (males) and 23.7 kg/m² (females). Hypothyroidism was the most common endocrine diagnosis. For females, kappa was highest for BR and PH in T1 (BR 0.65, PH 0.57) and T5 (BR 0.57, PH 0.65). For males, kappa was highest in T1 (0.73) and T2 (0.58). Grouping Tanner stages into prepuberty (T1), early to mid-puberty (T2-T3), and late puberty (T4-T5) showed greater agreement., Conclusion: Patients can reliably distinguish between "puberty" and "no puberty" using self-staging, though differentiating between later pubertal stages is more challenging. These findings help define the utility and limitations of self-staging during telemedicine visits., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Ebo, McCray, Bowers, Rose and Jones.)

Protein malnutrition during critical periods poses significant risks to reproductive health. Thus, this study aims to evaluate the immediate and delayed effects of a 30-day low-protein diet on the postnatal development of the male reproductive system. For so, male rats were fed a protein-deficient diet from postnatal day 30-60, followed by evaluations of testis, epididymis, and spermatozoa both at the end of the diet and after a 60-day recovery period. Testicular and epididymal weight was lowered in pubertal animals. Several histological alterations were found in the testis, such as acidophilic cells and vacuoles in the seminiferous epithelium, and sperm production was compromised. In the epididymis, the luminal compartment was diminished, and the stroma was enlarged both in the caput and cauda; in the cauda, the epithelial compartment was enlarged; the transit time of spermatozoa through this organ was diminished. Testosterone production was lowered. Spermatozoa's motility, mitochondrial activation, and acrosomal integrity were impaired, and several alterations in morphology were observed. After the recovery period, testicular and epididymal weight was restored. Tissue remodulation was observed in the epididymis, but the spermatozoa's transit time in this organ was not altered. Sperm and testosterone production, spermatozoa motility, mitochondrial activation, and acrosomal integrity were also restored. However, testicular histological alterations and spermatic morphological abnormalities were maintained in protein-restricted animals. Protein restriction during peripuberty impairs the reproductive maturation of pubertal Wistar rats, impairing testicular and epididymal function, with lasting effects even after dietary correction.

A successful control of sexual maturation is crucial for year-round production of lumpfish juveniles destined as cleaner fish in Atlantic salmon aquaculture. This study investigated the combined effects of photoperiod and temperature manipulations on sexual maturation and spawning in lumpfish females. Lumpfish juveniles were exposed to simulated natural and nine-month compressed annual photoperiods, with subsequent temperature elevation. Body weight (BW), condition factor (K), gonadosomatic index (GSI), ovarian development, plasma levels of 17β-estradiol (E2), testosterone (T) and 11-ketotestosterone (11-KT), and spawning were assessed. Compressing the natural photoperiod caused a clear increase and decrease in GSI, T, 11-KT and E2 towards and during the spawning period. Before the temperature elevation, GSI, T, 11-KT, E2 and ovarian development were advanced in the compressed photoperiod. After the temperature elevation, GSI, T, 11-KT and E2 fluctuated more in the compressed photoperiod, while in the natural photoperiod, E2 declined, and GSI, T and 11-KT increased. Spawning was advanced by 1 month in the compressed photoperiod compared to the natural photoperiod. Temperature elevation led to higher levels, earlier peaks and declines of T, 11-KT or E2 in both photoperiods, and advanced spawning by 1.5 months in the compressed photoperiod compared to the natural photoperiod. Temperature elevation also led to increased ovulation recruitment and increased cumulative weight of spawned eggs in the natural photoperiod. Compressing the natural photoperiod and elevating temperature can thus advance sexual maturation and spawning in lumpfish females. Due to the lower amounts of spawned egg weights in the high temperature compressed photoperiod, further studies on effects of photoperiod and timing of temperature manipulations on spawning, fecundity and egg quality could optimize the photothermal manipulations on lumpfish broodstock., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Mlingi et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Puberty is the critical developmental transition to reproductive capability driven by the activation of gonadotropin-releasing hormone (GnRH) neurons. The complex neural mechanisms underlying pubertal activation of GnRH secretion still remain unknown, yet likely include kisspeptin neurons. However, kisspeptin neurons reside in several hypothalamic areas and the specific kisspeptin population timing pubertal onset remains undetermined. To investigate this, we strategically capitalized on the differential ontological expression of the Kiss1 gene in different hypothalamic nuclei to selectively ablate just arcuate kisspeptin neurons (aka KNDy neurons) during the early juvenile period, well before puberty, while sparing RP3V kisspeptin neurons. Both male and female transgenic mice with a majority of their KNDy neurons ablated (KNDy ABL ) by diphtheria toxin treatment in juvenile life demonstrated significantly delayed puberty onset and lower peripubertal LH secretion than controls. In adulthood, KNDy ABL mice demonstrated normal in vivo LH pulse frequency with lower basal and peak LH levels, suggesting that only a small subset of KNDy neurons is sufficient for normal GnRH pulse timing but more KNDy cells are needed to secrete normal LH concentrations. Unlike prior KNDy ablation studies in rats, there was no alteration in the occurrence or magnitude of estradiol-induced LH surges in KNDy ABL female mice, indicating that a complete KNDy neuronal population is not essential for normal LH surge generation. This study teases apart the contributions of different kisspeptin neural populations to the control of puberty onset, demonstrating that a majority of KNDy neurons in the arcuate nucleus are necessary for the proper timing of puberty in both sexes., (© 2024 The Author(s). The FASEB Journal published by Wiley Periodicals LLC on behalf of Federation of American Societies for Experimental Biology.)

Background/objectives: Childhood obesity, particularly in girls, is linked to early puberty onset, heightening risks for adult-onset diseases. Addressing childhood obesity and precocious puberty is vital to mitigate societal burdens. Despite existing costly and invasive medical interventions, introducing lifestyle-based alternatives is essential. Our study investigates alternate-day fasting's (ADF) impact on pubertal development in normal-weight and high-fat diet (HFD)-induced obese female mice., Methods: Four groups of female mice were utilized, with dams initially fed control chow during and before pregnancy. Post-parturition, two groups continued on control chow, while two switched to an HFD. Offspring diets mirrored maternal exposure. One control and one HFD group were subjected to ADF. Morphometry and hormone analyses at various time points were performed., Results: Our findings demonstrate that ADF in normal-weight mice led to reduced body length, weight, uterine, and ovarian weights, accompanied by delayed puberty and lower levels of sex hormones and growth hormone (GH). Remarkably, GH treatment effectively prevented ADF-induced growth reduction but did not prevent delayed puberty. Conversely, an HFD increased body length, induced obesity and precocious puberty, and altered sex hormones and leptin levels, which were counteracted by ADF regimen. Our data indicate ADF's potential in managing childhood obesity and precocious puberty., Conclusions: ADF reduced GH and sex hormone levels, contributing to reduced growth and delayed puberty, respectively. Therefore, parents of normal-weight children should be cautious about prolonged overnight fasting. ADF prevented HFD-induced obesity and precocious puberty, offering an alternative to medical approaches; nevertheless, further studies are needed for translation into clinical practice., (© 2024. The Author(s).)

Pacific bluefin tuna (Thunnus orientalis) remains heavily depleted due to overexploitation. Aquaculture and stock enhancement based on artificial seedlings could be effective solutions to this problem. However, widespread adoption of seedling production is limited because spawning in captivity of bluefin tuna, a large pelagic top predator, requires much space, time, cost, and labour. To downsize and shorten their generation time, here, we show that xenogeneic germ cell transplantation enables a surrogate production of functional bluefin tuna sperm in hybrid little tuna (genus: Euthynnus), which attain sexual maturity at a smaller body size and shorter time. Intraperitonially transplanted bluefin tuna germ cells migrate towards and are incorporated into the gonads of little tuna larvae. These recipients produce functional donor-derived bluefin tuna sperm at a mere 8 months of age and 1 kg of body size. This result represents an advance toward compact, low-cost, and time-efficient seedling production that will improve the efficiency of bluefin tuna aquaculture., (© 2024. The Author(s).)

Goat production is affected by reproductive seasonality. In vitro embryo production (IVEP) could overcome this effect. This study aimed to evaluate the impact of the season of semen collection/freezing on IVEP of prepubertal goat oocytes and on sperm quality and functionality concerning capacitation. Semen from six fertile bucks was collected, pooled and cryopreserved in spring and autumn and used for IVEP of oocytes recovered during the breeding season. Oocytes were IVM in TCM-199 with hormones, EGF and cysteamine; fertilized and cultured in BO-IVF and BO-IVC media (IVF Bioscience, UK). Semen samples were assessed at 0 and 3 h after culture in capacitating (BO-IVF, CAP) and non-capacitating conditions for sperm plasma membrane and acrosome integrity, mitochondrial membrane potential (MMP), intracellular calcium and plasma membrane lipid disorder. Blastocyst production was higher with spring sperm compared to autumn (12.0% vs. 2.1%, respectively; p < .05). After CAP, acrosome reaction and intracellular calcium were higher (p < .05) in spring than autumn sperm. No differences were found in other sperm parameters. In conclusion, seasonal variations in the IVEP of prepubertal goats could be linked to differences in sperm ability to undergo in vitro capacitation., (© 2024 The Authors. Reproduction in Domestic Animals published by Wiley‐VCH GmbH.)

The main goals of this study were to document and compare the normal ranges of testicular haemodynamic parameters in pre- (aged 8-12 months; n = 4) and postpubertal (aged 24-259 months; n = 16) Miranda donkeys in the breeding season, and to correlate animal biometric data and testicular Doppler indices with basic semen quality parameters of sexually mature jacks. Colour and pulsed-Doppler ultrasonography were employed to assess blood flow in the left and right distal supratesticular artery (DsTA) and their marginal branches (marginal arteries-MA). Peak systolic velocity (PSV), end diastolic velocity (EDV), pulsatility index (PI) and resistive index (RI) were evaluated in both blood vessels, and TAMV (time-averaged mean velocity), TABF (total arterial blood flow) and TABF rate (TABF-R) were calculated for MA. The mean diameter of MA was greater (p < 0.05; 0.24 ± 0.05 vs. 0.19 ± 0.05 cm; mean ± SD) but TABF-R was less (p < 0.05; 0.004 ± 0.004 vs. 0.02 ± 0.01 mL/s/cm 3 ) in sexually mature donkeys compared with prepubertal animals. Apart from RI values for the right testicle of prepubertal donkeys, PI and RI were consistently greater (p < 0.05) in DsTA compared with MA. Significant correlations were found among select biometric and haemodynamic attributes of the testes (height, width and length, TV, TTV and PSV-ST) and ejaculate characteristics (volume, sperm defects-total, head and midpiece) in sexually mature donkeys (n = 8). The present results highlight the importance of scrotal ultrasonography for the reproductive assessment of jacks and provide reference values, based on the available subpopulation of Miranda donkeys that can be used in their clinical and reproductive management and research, or conservation programmes., (© 2024 Wiley‐VCH GmbH. Published by John Wiley & Sons Ltd.)

Puberty is a period of brain organization impacting the expression of social and sexual behaviors. Here, we assessed the effects of an acute pubertal stressor (immune challenge) on the expression of juvenile play (short-term) and sexual partner preference (long-term) in male rats. Juvenile play was assessed over ten trials at postnatal days (PND) (31-40) with age- and sex-matched conspecifics, and at PND35 males received a single injection of lipopolysaccharide (LPS, 1.5 mg/kg i.p.) or saline. Then, sexual partner preference was assessed at PND 60, 64, and 68, in a three-compartment chamber with a sexually receptive female and a male as potential partners simultaneously. The results confirmed that a single injection of LPS during puberty induced sickness signs indicative of an immune challenge. However, juvenile play was not affected by LPS treatment during the following days (PND36-40), nor was sexual behavior and partner preference for females in adulthood. These findings highlight that, while other studies have shown that LPS-induced immunological stress during puberty affects behavior and neuroendocrine responses, it does not affect juvenile play and sexual behavior in male rats. This suggests a remarkable resilience of these behavioral systems for adaptation to stressful experiences mediated by immune challenges during critical periods of development. These behaviors, however, might be affected by other types of stress., Competing Interests: Declaration of competing interest The authors declare that they have no conflict of interest., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Objective: To investigate whether maternal stress in pregnancy is associated with pubertal timing in girls and boys and to explore potential mediation by childhood body mass index (BMI) and childhood psychosocial stress., Design: Cohort study., Setting: Not applicable., Patients: In total, 14,702 girls and boys from the Puberty Cohort, nested within the Danish National Birth Cohort., Intervention: Maternal stress was obtained from a computer-assisted telephone interview in gestational weeks 30-32 as maternal life stress and emotional distress in pregnancy using questions on the basis of validated screening tools. Maternal life stress and emotional distress in pregnancy were analyzed separately and in an interaction analysis., Main Outcome Measures: Pubertal timing was measured half-yearly from age 11 years and throughout pubertal development and assessed as Tanner stages 1-5 (breast and pubic hair development in girls and genital and pubic hair development in boys), menarche in girls, voice break and first ejaculation in boys, and occurrence of acne and axillary hair in both girls and boys. A combined estimate for overall pubertal timing was derived using Huber-White robust variance estimation. Mean differences in age at attaining the pubertal milestones according to prenatal exposure to no (reference), low-, moderate-, or high-maternal stress in pregnancy were estimated using a multivariable censored regression model. Potential mediation by childhood BMI and childhood psychosocial stress was investigated in separate models., Results: After adjustment for potential confounding factors, prenatal exposure to high-maternal life stress (combined estimate: -1.8 months [95% CI, -2.7 to -0.8] and -0.9 months [95% CI, -1.8 to 0.0]), high maternal emotional distress (combined estimate: -1.5 months [95% CI, -2.5 to -0.5] and -1.7 months [95% CI, -2.8 to -0.7]), and both high-maternal life stress and emotional distress (combined estimate: -2.8 months [95% CI, -4.2, to -1.4] and -1.7 months [95% CI, -3.1 to -0.2]) were associated with earlier pubertal timing in girls and boys, respectively. The associations were not mediated by childhood BMI or childhood psychosocial stress., Conclusions: Prenatal exposure to maternal stress in pregnancy was associated with earlier pubertal timing in girls and boys in a dose-dependent manner. The associations were not mediated by childhood BMI or childhood psychosocial stress., Competing Interests: Declaration of Interests A.G.S. has nothing to disclose. N.B. has nothing to disclose. T.B.H. has nothing to disclose. C.H.R.H. has nothing to disclose., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

The prevalence of depression significantly increases during puberty and adolescence. Puberty is the period during which sexual maturity is attained, while adolescence persists beyond puberty and includes physiological, social, emotional, and cognitive maturation. A stressor that has been shown previously to induce depression is chronic sleep disruption. Probiotics can prevent stress-induced depression. However, it was unclear whether probiotics could prevent depression following chronic sleep disruption and what mechanism may be involved. Therefore, we investigated whether pubertal probiotic treatment could prevent depression-like behavior in mice following chronic sleep disruption. We also examined whether probiotic treatment could improve sleep quality, and increase serotonin, tryptophan, glucose, and L-lactate concentrations in chronically sleep-disrupted mice. We hypothesized that probiotic treatment would prevent depression-like behavior, improve sleep quality, and increase serotonin, tryptophan, glucose, and L-lactate concentrations in sleep-disrupted mice. Male and female mice (N=120) received cannula and electroencephalogram (EEG) electrode implants at postnatal day (PND) 26. Mice received Lacidofil® or Cerebiome® probiotics (PND 33-51) and were sleep-disrupted for the first 4 hours of the light phase (sleep period) (PND 40-51). Hippocampal L-lactate and glucose concentrations and sleep were measured over a 24-h period (PND 48-49). Depression-like behaviour was evaluated using tail suspension (PND 49) and forced swim tests (PND 50). Chronic sleep disruption increased depression-like behaviour and NREM duration in the dark phase, and reduced all metabolites and neuromodulating biomolecules measured within the brain. However, mice treated with probiotics did not display depression-like behaviour or decreased hippocampal L-lactate following chronic sleep disruption. Cerebiome prevented decreases to prefrontal serotonin and hippocampal glucose concentrations, while Lacidofil increased NREM duration in the latter half of the light phase. The current study not only replicates previous findings linking chronic sleep disruption to depression, but also demonstrates that pubertal probiotic treatment can mitigate the effects of chronic sleep disruption on depression-like behaviour and on the neural mechanisms underlying depression in a strain-dependent manner., Competing Interests: Declaration of Competing Interest We have no conflict of interest to declare., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Objective: Age at pubertal onset has decreased over the recent decades. Early maturing girls have longer puberty duration, and higher peak height velocity (PHV) than late maturing girls. To what extent this is generated by increased insulin-like growth factor-I (IGF-I), fat mass, or fasting insulin levels is currently unknown., Design, Setting, Participants: A population-based study-part of the COPENHAGEN puberty study-longitudinal part. Eighty-one girls evaluated biannually for a median of 10 (2-15) visits for a total of 815 evaluations., Methods: Pubertal staging, anthropometric measures, PHV, skin fold thickness (SFT), and IGF-I and fasting insulin levels were measured., Results: Early maturing girls achieved similar final height compared to late maturing girls (166.1 vs 167.1 cm, P = .36). Early pubertal onset was associated with significantly greater PHV (8.7 vs 7.4 cm/year, P < .001) and a longer puberty duration (age at onset of breast development to age at PHV [1.8 vs 1.1 years, P < .001]) compared with late maturation. After correcting for age at pubertal onset, neither body mass index, SFT, nor IGF-I levels differed between early vs late maturing girls. By contrast, fasting insulin levels were significantly higher in early compared with late maturing girls 1.5, 2.0, and 3.0 years after pubertal onset (all P = .039)., Conclusion: Growth velocity was higher and more prolonged in early compared with late maturing girls and associated with higher insulin levels. Thus, the higher insulin levels may compensate for the shorter total growth period by intensifying the pubertal growth period., Clinical Trial Registration Number: NCT01411527., Competing Interests: Conflict of interest: The authors have no conflict of interest., (© The Author(s) 2024. Published by Oxford University Press on behalf of European Society of Endocrinology. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

The study of reproductive biology is an important tool in identifying protective measures to preserve fish stocks, providing essential data for a reliable management system that ensures a balance between the environment and the economy. This study aims to analyze the first sexual maturity and type of spawning of the fish Conodon nobilis (Linnaeus, 1758) on the Amazon coast, specifically in the Gulf Maranhense region. 360 specimens were obtained from commercial fishing activity in the community of Raposa-MA during the period from January to December 2021. Biometric data were recorded, and the gonadal maturation stages were determined through macro (maturation scale) and microscopic (histology) analyzes. Sex ratio, mean length of first sexual maturation and type of spawning were determined. Negative allometric growth was recorded for both sexes, indicating a greater increase in length than in weight, and the length varied from 11 to 31.8 cm and the sex ratio was 1 male:1.5 female. Individuals in all stages of maturation were observed throughout the year, with a predominance of individuals in spawning capacity and reproductive peaks in January, April and May, indicating that the species presents multiple spawning. The length at first sexual maturity (L50) for females was 18.41 cm and for males was 18.91 cm. Knowledge of the mean size at sexual maturity can help define appropriate regulations for fishing, ensuring that individuals have the opportunity to reproduce at least once before being captured.

Reproductive hormones are essential to mating systems, behavior, fertility, gestation, parturition, and lactation in mammals and understanding the role of hormones in these processes is essential for species conservation. Sirenia is a unique order of marine mammals that include manatees, dugongs, and the extinct Steller's sea cow. Extant Sirenian species are all listed as vulnerable due to habitat loss, cold stress, boat strike trauma, harmful algal bloom toxicity, entanglements, and illegal hunting. Therefore, successful reproduction is essential to maintaining and increasing Sirenian populations. Understanding Sirenian reproductive behavior, endocrinology, and mating strategies will aid conservation and management efforts to protect and provide the proper conditions for successful reproduction. The objectives of this review were to synthesize the current knowledge regarding reproductive cycles and endocrinology of Sirenians and identify knowledge gaps for future investigation. The current literature on Sirenian reproductive physiology reports reproductive seasonality, sexual maturation, estrous cyclicity and acyclicity, pregnancy, and sex differences. However, there remain significant knowledge gaps on the cyclicity and pulsatile release of gonadotropins, maturation in females, and characterization of pregnancy hormone profiles throughout gestation. To date, there is no explanation for confirmed pattern for ovarian acyclicity, nor understanding of the function of the numerous accessory corpus luteum described in manatees. Research including a greater number of longitudinal and postmortem studies on a wider variety of wild manatee populations are important first steps. Taken together, understanding the reproductive endocrinology of these vulnerable and threatened species is critical for policy and management decisions to better inform protection initiatives., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Heat stress due to climate warming can significantly affect the synthesis of sex hormones in male adolescents, which can impair the ability of the hypothalamus to secrete gonadotropin-releasing hormone on the hypothalamic-pituitary-gonadal axis, which leads to a decrease in luteinizing hormone and follicle-stimulating hormone, which ultimately negatively affects spermatogenesis and testosterone synthesis. For optimal spermatogenesis, the testicular temperature should be 2-6 °C lower than body temperature. Heat stress directly affects the testes, damaging them and reducing testosterone synthesis. Additionally, chronic heat stress abnormally increases the level of aromatase in Leydig cells, which increases estradiol synthesis while decreasing testosterone, leading to an imbalance of sex hormones and spermatogenesis failure. Low levels of testosterone in male adolescents lead to delayed puberty and incomplete sexual maturation, negatively affect height growth and bone mineral density, and can lead to a decrease in lean body mass and an increase in fat mass. In order for male adolescents to acquire healthy reproductive capacity, it is recommended to provide sufficient nutrition and energy, avoid exposure to heat stress, and provide foods and supplements to prevent or repair testosterone reduction, germ cell damage, and sperm count reduction caused by heat stress so that they can enter a healthy adulthood.

Background: Morphological and histological examination of the testes can provide a suitable insight into the health of the reproductive system., Aim: The objective of the current study was to investigate the morphological and histological features of the testes of local pigeons ( Columba livia domestica ) at mature and immature stages of age., Methods: Two groups of collected specimens underwent macroscopic and microscopic investigation to evaluate and compare the main general properties of their testes., Results: The findings indicated that the testis has an oval shape in both pre-puberty and post-puberty stages, situated on the inner side of the kidney towards the caudal extreme of the lungs. However, the left testis was bigger than those on the right side. In the pre-puberty stage group, the testicular parenchyma was small, and almost collapsed seminiferous tubules containing a single layer of Spermatogonia and Sertoli cells. In contrast, in the post-puberty stage, the parenchyma space between seminiferous tubules was small, and tubules adhered closely to each other. Also, mature cells including sertoli, spermatogonia, and spermatocytes were noticed to spread within the tubules., Conclusion: The change in the histological structure of testes before and after maturity may help to evaluate the complexity of the male reproductive system of pigeons and draw attention to the organization of sex hormones and the function of several types of cells within the testes., Competing Interests: The authors confirm that they have no conflicts of interest.

Aim: This study aimed to evaluate the ovarian tissue culture and in vitro follicle growth as safer alternatives to cryopreservation for generating in vitro fertilization (IVF)-ready mature oocytes from prepubertal mice without the risk of cancer cell contamination., Methods: Ovaries from prepubertal B6D2F1 mice were cultured in α-minimum essential medium supplemented with an estrogen receptor antagonist, ICI 182780. Culture duration was investigated to identify the optimal timeframe for follicle growth and oocyte maturation. Follicles were isolated mechanically or using 1 mg/mL collagenase and cultured in Matrigel matrix or polyvinylpyrrolidone. Oocyte development at metaphase II was induced by in vitro maturation, followed by IVF., Results: The optimal culture duration was 2-4 days, and tissues cultured beyond this period showed significant follicular degeneration. ICI 182780 supplementation resulted in the recovery of 20.5 follicles per ovary compared with 9.5 follicles in non-supplemented cultures (p < 0.05). Of the 452 isolated follicles, 237 (52.4%) showed growth, 150 (33.2%) underwent germinal vesicle breakdown, and 18 (4.0%) reached metaphase II. However, none of the metaphase II oocytes were successfully fertilized after IVF. Matrigel demonstrated a significantly higher in vitro maturation rate compared with polyvinylpyrrolidone in a comparative analysis of culture matrices (p < 0.001)., Conclusions: This study highlighted ovarian tissue culture and in vitro growth as effective strategies for producing mature oocytes from prepubertal mice. Further studies are required to overcome fertilization hurdles and understand the mechanisms that improve post-IVF embryo viability., (© 2024 The Author(s). Journal of Obstetrics and Gynaecology Research published by John Wiley & Sons Australia, Ltd on behalf of Japan Society of Obstetrics and Gynecology.)

The current literature suggests that relaxin-3/relaxin/insulin-like family peptide receptor 3 (RLN-3/RXFP-3) system is involved in the pathophysiology of affective disorders because the results of anatomical and pharmacological studies have shown that the RLN-3 signaling pathway plays a role in modulating the stress response, anxiety, arousal, depression-like behavior, and neuroendocrine homeostasis. The risk of developing mental illnesses in adulthood is increased by exposure to stress in early periods of life. The available data indicate that puberty is especially characterized by the development of the neural system and emotionality and is a "stress-sensitive" period. The presented study assessed the short-term changes in the expression of RLN-3 and RXFP-3 mRNA in the stress-dependent brain regions in male pubertal Wistar rats that had been subjected to acute stress. Three stressors were applied from 42 to 44 postnatal days (first day: a single forced swim; second day: stress on an elevated platform that was repeated three times; third day: restraint stress three times). Anxiety (open field, elevated plus maze test) and anhedonic-like behavior (sucrose preference test) were estimated during these tests. The corticosterone (CORT) levels and blood morphology were estimated. We found that the RXFP-3 mRNA expression decreased in the brainstem, whereas it increased in the hypothalamus 72 h after acute stress. These molecular changes were accompanied by the increased levels of CORT and anxiety-like behavior detected in the open field test that had been conducted earlier, that is, 24 h after the stress procedure. These findings shed new light on the neurochemical changes that are involved in the compensatory response to adverse events in pubertal male rats and support other data that suggest a regulatory interplay between the RLN-3 pathway and the hypothalamus-pituitary-adrenal axis activity in the mechanisms of anxiety-like behavior., (© 2024 Wiley Periodicals LLC.)

Exposure to stressors during puberty can disrupt normal development and possibly increase susceptibility to neurodegenerative disorders later in life. However, the mechanisms underlying the relationship between pubertal stress exposure and neurodegeneration remain unclear. As such, the current study was designed to examine the effects of pubertal antimicrobial (AMNS) and lipopolysaccharide (LPS) treatments on intestinal and blood-brain-barrier (BBB) permeability in male and female mice. Moreover, we also examined the sex-specific effects of pubertal AMNS and LPS treatments on gross motor activity, heart rate, and core body temperature. At four weeks of age, male and female CD1 mice were implanted with the G2 HR E-Mitter telemetry system. At five weeks of age, mice received 200 μL of broad-spectrum antimicrobial or water, through oral gavage, twice daily for seven days. Mice received an intraperitoneal injection of either saline or LPS at six weeks of age. BBB and intestinal permeability were examined 24 h, 72 h, and one week post-LPS/saline treatment. Telemetric data was collected for 48 h post-LPS/saline treatment. The results showed that pubertal AMNS and LPS treatments increased sickness behaviours and decreased body temperature and heart rate, in a sex-dependent manner. Furthermore, pubertal AMNS and LPS treatments resulted in sex-dependent regional increases in BBB permeability 24 h and 72 h post-LPS/saline treatment, while global increases in BBB permeability were only observed one week post-LPS/saline treatment. These results further our understanding of the combined effects of AMNS and LPS treatments on physiology and on the enduring negative changes observed following pubertal exposure to stressors., Competing Interests: Declaration of competing interest None., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

The red spotted grouper Epinephelus akaara is a marine species of economic importance and also at risk of extinction. This study investigated the effects of high water temperature on the growth and maturation of juvenile E. akaara females. From 160-420 days post-hatching (dph), the fish were maintained under natural water temperature (NT) and a constant high-water temperature (HT). From 240 dph, both the total length and body weight in the HT group were greater than in NT group. After 360 dph, the gonadosomatic index was also increased in the HT group compared to NT group. Mature oocytes were only observed in the HT group at 330, 360, and 390 dph. Both kiss1 and kiss2 levels increased at 240 and 270 dph in both groups; however, they were greater in the HT group at 240 dph. Similarly, gpr54 levels after 360 dph were greater in the HT group, suggesting that kisspeptin is related to maturation via its receptor gpr54. Levels of fshβ and lhβ were greater in the HT group after 360 dph. Estradiol-17β (E 2 ) levels after 160 dph (except 300 dph) were greater in the HT group than in the NT group, suggesting that the higher E 2 levels trigger maturation, and is related to increased fshβ and lhβ. This study provides evidence that high water temperature is effective in accelerating growth and triggering early maturation of juvenile E. akaara, via regulating gpr54, fshβ, lhβ, and E 2 levels., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

Regeneration, regrowing lost and injured body parts, is an ability that generally declines with age or developmental transitions (i.e. metamorphosis, sexual maturation). Regeneration is also an energetically costly process, and trade-offs occur between regeneration and other costly processes such as growth, or sexual reproduction. Here we investigate the interplay of regeneration, reproduction, and developmental stage in the segmented worm Platynereis dumerilii. P. dumerilii can regenerate its whole posterior body axis, along with its reproductive cells, thereby having to carry out the two costly processes (somatic and germ cell regeneration) after injury. We specifically examine how developmental stage affects the success of germ cell regeneration and sexual maturation in developmentally young versus developmentally old organisms. We hypothesized that developmentally younger individuals (i.e. with gametes in early mitotic stages) will have higher regeneration success than the individuals at developmentally older stages (i.e. with gametes undergoing meiosis and maturation). Surprisingly, older amputated worms grew faster and matured earlier than younger amputees. To analyze germ cell regeneration during and after posterior regeneration, we used Hybridization Chain Reaction for the germline marker vasa. We found that regenerated worms start repopulating new segments with germ cell clusters as early as 14 days post amputation. In addition, vasa expression is observed in a wide region of newly-regenerated segments, which appears different from expression patterns during normal growth or regeneration in worms before gonial cluster expansion., (Copyright © 2024 Elsevier Inc. All rights reserved.)

This study examines the role of N-acetylglucosamine kinase (NAGK) in initiating puberty in female mice. We employed real-time quantitative reverse transcription polymerase chain reaction (RT-qPCR) and immunofluorescence to measure NAGK expression in the hypothalamic-pituitary-ovarian axis across various developmental stages: infant, prepuberty, puberty, and adult. We further investigated the impact of Nagk gene knockdown on puberty in female mice. This included assessing the expression of puberty-related genes both in vivo and in vitro, GT1-7 cells proliferation and apoptosis, concentrations of GnRH and Kisspeptin, puberty onset timing, serum levels of progesterone (P 4 ) and estradiol (E 2 ), and ovarian morphology. Results revealed that Nagk mRNA is present in the hypothalamus, pituitary, and ovaries throughout different developmental stages in female mice. In the hypothalamus, Nagk mRNA levels were comparable during infant and prepuberty, lowest during puberty, and highest in adult. In the pituitary, Nagk mRNA peaked in adult, with no significant variation between infant, prepuberty, and puberty. In the ovaries, Nagk mRNA levels increased during puberty and peaked in adult. NAGK is predominantly located in the arcuate nucleus (ARC), periventricular nucleus (PeN), dorsomedial hypothalamic nucleus (DMH), paraventricular nucleus (PVN), adenohypophysis, and in the ovarian oocytes, interstitium, and granulosa cells across all developmental stages in female mice. Nagk knockdown in GT1-7 cells decreased the transcriptional level of Gnrh, Kiss1, Gpr54, Igf1 and Mapk14 mRNA and cell proliferation but increased the level of β-catenin mRNA and cell apoptosis, while reducing GnRH secretion. Following ICV injection, Nagk gene knockdown mice exhibited delayed the timing of vaginal opening (VO) and reduced hypothalamic levels of Gnrh, Kiss1, Gpr54, Igf1, Mapk14, and β-catenin mRNA. Additionally, serum concentrations of E 2 in Nagk gene knockdown mice were significantly lower compared to the control group. These findings indicate that Nagk regulates the expression of Gnrh and Kiss1 mRNA in GT1-7 cells, affects hypothalamus Gnrh mRNA levels and serum E 2 concentration, and that its knockdown can delay puberty onset in female mice., Competing Interests: Declaration of competing interest The authors declare no conflicts of interest with regard to this study., (Copyright © 2024 Elsevier Inc. All rights reserved.)

This study aimed to investigate the differences between productive and reproductive performance traits of sexually precocious and non-sexually precocious Nellore heifers and to evaluate the genetic correlation of sexual precocity with traits of economic importance. For this purpose, 300,000 Nellore heifers were evaluated for reproductive traits: heifer pregnancy (HP) at 14 (HP 14 ), 18 (HP 18 ), and 24 (HP 24 ) months; heifer rebreeding (HR); number of progenies up to 53 months (NP 53 ); and probability of the cow remaining in the herd until 76 months with at least 3 progenies (Stay). The growth-related traits evaluated included female yearling weight (YW); average daily gain from weaning to yearling (ADG W-Y ); weight at maturity (MW); weaning weight of first progeny (WW prog ); and female visual scores at yearling for conformation (Conf), precocity (Prec) and muscling (Musc). The effects of female YW and ADG W-Y in six categories on HP 14 , HP 18 , and HP 24 were analyzed using Generalized linear mixed models (GLMM). Furthermore, a linear mixed model was used to evaluate the impact of HP on WW prog , MW, and reproductive performance (NP 53 and Stay). Genetic correlations of HP evaluated in different months with growth and reproductive traits were estimated using a bivariate animal model. Precocious heifers (HP 14 ) were lighter for YW and MW but had greater ADG W-Y than HP 18 and HP 24 . The probability for HP 14 , HP 18 , and HP 24 increased as the classes of YW and ADG W-Y increased. However, heifers weighing more than 326 kg had a slight reduction in the probability of becoming pregnant at HP 14 and HP 18 . Precocious heifers (HP 14 and HP 18 ) produced their first progeny by 3 % lighter than HP 24 , although they had a greater NP 53 . Precocious heifers at 18 months (HP 18 ) were 3 % and 6.8 % more likely to remain in the herd than HP 14 and HP 24 heifers, respectively. Genetic correlations between growth traits (WW, YW, ADG W-Y, and MW) and heifer pregnancy (HP 14 , HP 18 , and HP 24 ) ranged from weak (r g  = 0.27 ± 0.05) to moderate (r g  = -0.47 ± 0.07). The genetic correlation between HR and HP was stronger for HP 24 (0.75) against HP 14 (0.58) and HP 18 (0.64). Although, the genetic correlation between NP 53 and Stay with HP 14 was higher (r g  = 0.53 and 0.45) than those observed for HP 18 (r g  = 0.46 and 0.38) and HP 24 (r g  = 0.35 and 0.39). The genetic correlation estimates between HP and visual scores were moderate and favorable for HP 14 . Selecting HP 14 is beneficial for production systems because it increases the NP 53 during the productive life without compromising heifer productivity or reproductive performance. However, attention should be given to improving the HR of heifers who become pregnant early., (Copyright © 2024 Elsevier Inc. All rights reserved.)

There has been an alarming trend toward earlier puberty in girls, suggesting the influence of an environmental factor(s). As the reactivation of the reproductive axis during puberty is thought to be mediated by the hypothalamic neuropeptides kisspeptin and gonadotropin-releasing hormone (GnRH), we asked whether an environmental compound might activate the kisspeptin (KISS1R) or GnRH receptor (GnRHR). We used GnRHR or KISS1R-expressing HEK293 cells to screen the Tox21 10K compound library, a compendium of pharmaceuticals and environmental compounds, for GnRHR and KISS1R activation. Agonists were identified using Ca2+ flux and phosphorylated extracellularly regulated kinase (p-ERK) detection assays. Follow-up studies included measurement of genes known to be upregulated upon receptor activation using relevant murine or human cell lines and molecular docking simulation. Musk ambrette was identified as a KISS1R agonist, and treatment with musk ambrette led to increased expression of Gnrh1 in murine and human hypothalamic cells and expansion of GnRH neuronal area in developing zebrafish larvae. Molecular docking demonstrated that musk ambrette interacts with the His309, Gln122, and Gln123 residues of the KISS1R. A group of cholinergic agonists with structures similar to methacholine was identified as GnRHR agonists. When applied to murine gonadotrope cells, these agonists upregulated Fos, Jun, and/or Egr1. Molecular docking revealed a potential interaction between GnRHR and 5 agonists, with Asn305 constituting the most conservative GnRHR binding site. In summary, using a Tox21 10K compound library screen combined with cellular, molecular, and structural biology techniques, we have identified novel environmental agents that may activate the human KISS1R or GnRHR., (Published by Oxford University Press on behalf of the Endocrine Society 2024.)

The horned octopod Eledone cirrhosa, a medium-sized species found in Arabian Gulf off Saudi Arabia, was collected monthly from the Arabian Gulf off Dammam city during January to December 2022. Samples were dissected and prepared for examination using transmission electron microscopy. During genital maturation, seminiferous tubules are established in the testis, with active spermatogonia dividing. Spermatocytes 1 are observed in the tubule, followed by an increase in spermatogonia and spermatocytes in August. Spermiogenesis begins, with spherical spermatids evolving into elongated spermatids. In September, active spermatogonia, meiotic divisions, and increased spermiogenesis continue. Spermatozoa appear in Needham's pouch, indicating sexual maturity. The ovary undergoes various stages of development, with oocytes at stage I in June and July, followed by stage II in October and November. In stage III, follicular cords invade the oocyte's cytoplasm, forming numerous lipid inclusions and protein granules. The cytoplasm contains cisternae of endoplasmic reticulum and a poorly developed Golgi apparatus. Stage IV occurs in November, characterized by the maximum development of follicular cords and the beginning of vitellogenesis. The ooplasm contains numerous lipid inclusions, a syncytium, and secretory cells. From December, stage V oocytes are mainly present, indicating the activity phase of maximum secretion. Yolk platelets accumulate in the oocyte ooplasm, and chorion forms at the zona pellucida. In January, the first smooth eggs are found in some octopuses' ovary, with their proportion increasing steadily. This study aimed to investigate the mitogenic action of gonadotropin and identify the periods of intense cell multiplication during the sexual cycle using cytological methods.

Context: The hypothalamic-pituitary-gonadal axis's transient activity in infancy, i.e, minipuberty, is considered crucial for male reproductive function. Historically, minipuberty has been considered a passive response triggered by the withdrawal of placental steroids at birth. However, given its potential link to adult reproductive function, we hypothesize that minipuberty is a partially genetically regulated process, suggesting a link between the genetic architecture of reproductive hormone concentrations across lifespan., Objective: To investigate the association of UK Biobank Study-based polygenic scores (PGS) of adult total testosterone (T) and sex hormone-binding globulin (SHBG) concentrations with trajectories of reproductive hormones concentrations in male infants., Design: Prospective, longitudinal birth cohort (The COPENHAGEN Minipuberty Study, 2016-2018, ClinTrial: NCT02784184). Individual PGSs in male infants derived from published literature were calculated for total T and SHBG. The associations with mean SD scores (SDS) of reproductive hormone concentrations in infancy were tested., Setting: Population-based., Patients or Other Participants: Healthy, male, term, singleton newborns were followed with repeated clinical examinations including blood sampling during a 1-year follow-up (n = 109)., Main Outcome Measures: Circulating reproductive hormone concentrations., Results: T-PGSadult were significant associated with mean T-SDSinfancy, mean SHBG-SDSinfancy, and mean LH-SDSinfancy (P = .02, <.001 and .03, with r2 = 0.05, 0.21 and 0.04, respectively). SHBG-PGSadult was significantly associated with mean SHBG-SDSinfancy (P < .001, r2 = 0.18). T-PGSadult explained 5% and 21% of the phenotypic variation in infancy of mean T-SDSinfancy and SHBG-SDSinfancy, respectively., Conclusion: Our findings suggest that the genetic architecture underlying total T and SHBG in adults also associates with hormone concentrations and their trajectories during infancy., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Endocrine Society. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

A total of 381 specimens of the tilapia Oreochromis mossambicus collected monthly from May 2017 to May 2018 in the Laguna de Los Patos, Cumaná, Venezuela, to evaluate reproductive parameters of this non-native species. Significant differences were found in relation to average height and weight between males and females, with the highest values in males. The sex ratio was 1:1.5 (males:females), which deviates significantly from the expected 1:1 ratio. The mean length of sexual maturity (Lm50) was 18.0 cm in females and 20.1 cm in males, reflecting that females mature at smaller sizes than males. The monthly variations of the gonadosomatic index (GSI) and the stages of sexual maturity show two reproductive peaks during the study, in October 2017 and April 2018, coinciding with the rainy and dry seasons in the region respectively. The condition factor (CF) showed significant differences between months, but not between sexes, with an average of 1.87 in females and 1.84 in males. The average absolute fecundity was 921 ± 604.6 eggs per fish, with a relative fecundity of 8.36 ± 3.09 eggs per gram of fish. Differences in oocyte size in mature females confirm that the species can spawn repeatedly over a period, which is considered an important factor for the establishment of tilapia in non-native environments.

Ghrelin has effects that range from the maturation of the central nervous system to the regulation of energy balance. The production of ghrelin increases significantly during the first weeks of life. Studies have addressed the metabolic effects of liver-expressed antimicrobial peptide 2 (LEAP2) in inhibiting the effects evoked by ghrelin, mainly in glucose homeostasis, insulin resistance, and lipid metabolism. Despite the known roles of ghrelin in the postnatal development, little is known about the long-term metabolic influences of modulation with the endogenous expressed growth hormone secretagogue receptor (GHSR) inverse agonist LEAP2. This study aimed to evaluate the contribution of GHSR signalling during perinatal phases, to neurodevelopment and energy metabolism in young animals, under inverse antagonism by LEAP2[1-14]. For this, two experimental models were used: (i) LEAP2[1-14] injections in female rats during the pregnancy. (ii) Postnatal modulation of GHSR with LEAP2[1-14] or MK677. Perinatal GHSR modulation by LEAP2[1-14] impacts glucose homeostasis in a sex and phase-dependent manner, despite no effects on body weight gain or food intake. Interestingly, liver PEPCK expression was remarkably impacted by LEAP2 injections. The observed results suggests that perinatal LEAP2 exposure can modulate liver metabolism and systemic glucose homeostasis. In addition, these results, although not expressive, may just be the beginning of the metabolic imbalance that will occur in adulthood.

Early-life stressors can affect reproductive development and change responses to adult stress. We tested if resource scarcity in the form of limited bedding and nesting (LBN) from postnatal days (PND) 4 to 11 delayed sexual maturation in male and female mice and/or altered the response to an acute, layered, psychosocial stress (ALPS) in adulthood. Contrary to the hypotheses, age and mass at puberty were unaffected by the present application of LBN. Under basal conditions and after ALPS, corticosterone concentrations in males, diestrous females, and proestrous females reared in standard (STD) or LBN environments were similar. ALPS disrupts the luteinizing hormone (LH) surge in most mice when applied on the morning of proestrus; this effect was not changed by resource scarcity. In this study, the paucity of effects in the offspring may relate to a milder response of CBA dams to the paradigm. While LBN dams exited the nest more often and their offspring were smaller than STD-reared offspring on PND11, dam corticosterone concentrations were similar on PND11. To test if ALPS disrupts the LH surge by blunting the increase in excitatory GABAergic input to gonadotropin-releasing hormone (GnRH) neurons on the afternoon of proestrus, we conducted whole-cell voltage-clamp recordings. The frequency of GABAergic postsynaptic currents in GnRH neurons was not altered by LBN, ALPS, or their interaction. It remains possible that ALPS acts at afferents of GnRH neurons, changes response of GnRH neurons to input, and/or alters pituitary responsiveness to GnRH and that a more pronounced resource scarcity would affect the parameters studied., Competing Interests: The authors declare no competing financial interests., (Copyright © 2024 Gibson and Moenter.)

Context: The regulation of pubertal timing and reproductive axis maturation is influenced by a myriad of physiologic and environmental inputs yet remains incompletely understood., Objective: To contrast differences in bile acid isoform profiles across defined stages of reproductive maturity in humans and a rat model of puberty and to characterize the role of bile acid signaling via hypothalamic expression of bile acid receptor populations in the rodent model., Methods: Secondary analysis and pilot studies of clinical cohorts, rodent models, ex vivo analyses of rodent hypothalamic tissues. Bile acid concentrations is the main outcome measure., Results: Lower circulatory conjugated:deconjugated bile acid concentrations and higher total secondary bile acids were observed in postmenarcheal vs pre-/early pubertal adolescents, with similar shifts observed in infantile (postnatal day [PN]14) vs early juvenile (PN21) rats alongside increased tgr5 receptor mRNA expression within the mediobasal hypothalamus of female rats. 16S rRNA gene sequencing of the rodent gut microbiome across postnatal life revealed changes in the gut microbial composition predicted to have bile salt hydrolase activity, which was observed in parallel with the increased deconjugated and increased concentrations of secondary bile acids. We show that TGR5-stimulated GnRH release from hypothalamic explants is mediated through kisspeptin receptors and that early overexpression of human-TGR5 within the arcuate nucleus accelerates pubertal onset in female rats., Conclusion: Bile acid isoform shifts along stages of reproductive maturation are conserved across rodents and humans, with preclinical models providing mechanistic insight for the neuroendocrine-hepatic-gut microbiome axis as a potential moderator of pubertal timing in females., (© The Author(s) 2024. Published by Oxford University Press on behalf of the Endocrine Society.)

This study investigates effects of subtle methodological choices on the estimation and biological interpretation of age, growth and reproductive parameters for harbour porpoises. The core analyses are based on a focal Norwegian data set built on samples from 134 harbour porpoises caught incidentally in gillnet fisheries along the Norwegian coast during autumn 2016 and spring 2017. Two contrasting practices for interpretation of seasonal and ontogenetic characteristics of tooth growth layer formation resulted in significant age differences among spring samples of young porpoises and for older animals across seasons. In turn, these differences affected estimates of age at maturity and asymptotic lengths, respectively. We also found significant differences in male age at maturity between two well-documented maturity criteria and between mathematical estimators of age at maturity for both sexes. Two different criteria for corpus albicans classification furthermore resulted in different patterns of ovarian corpora accumulation, which may affect some estimates of fecundity rates and contaminant loads. Both corpora accumulation patterns were also found in reanalysed data from German and Greenlandic porpoises. Based on tabulated overviews of methodological choices made in previous harbour porpoise studies, we argue that several of the issues mentioned above have wider relevance and may affect the validity of meta-analyses as a tool for estimating harbour porpoise sensitivity to extrinsic pressures. Differences in cause of death (COD) composition between data sets can have a similar effect. We demonstrate this in a meta-analysis of published harbour porpoise pregnancy rates, showing significantly higher values for trauma-killed samples compared to samples comprising mixed COD categories. COD also affected the estimated impacts of three previously analysed extrinsic predictors as well as an added predictor for vessel noise levels. We discuss the potential contributions of methodological, biological and anthropogenic factors in shaping observed regional differences in estimates of harbour porpoise life history parameters., Competing Interests: The authors have read the journal’s policy and have NO competing interests., (Copyright: © 2024 Frie, Lindstrom. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Aspects of the reproductive biology of Donax striatus were studied from individuals collected from Gado Bravo Beach in the municipality of Tibau do Norte, state of Rio Grande do Norte, Brazil. Donax striatus is a dioic species without external (on the shell) or internal (gonads) macroscopic dimorphism. Thus, a microscopic examination of the reproductive cells is necessary. For the characterization of the gonadal development stages and determination of the size at first sexual maturity (L50), 30 specimens were selected monthly between February 2021 and January 2022 and submitted to histological processing. The condition index (CI) of each individual was estimated and monthly variations were statistically assessed. The size at first maturity (L50) was estimated to be 14.2 mm in shell length. To foster conservation of the species, catches of individuals larger than 14.2 mm is recommended. The lowest condition indices were found in the dry season, with a greater occurrence of organisms in the elimination stage and exhibiting gonad tissue reorganization. Higher indices were found in the rainy season, with the presence of mature individuals. The continuous nature of gametogenesis in Donax stritatus reflects the influence of rainfall in the region. Males and females have peak gamete elimination with pauses during the year, but with the presence of maturing and eliminating individuals throughout the year. As shellfish gathering targeting Donax striatus is excessive on Gado Bravo Beach in the state of Rio Grande do Norte, it is hoped that the results of the present study can contribute to the establishment of management measures for the activity and conservation strategies for the species.

Conflicting data exist as to how mammary epithelial cell proliferation changes during the reproductive cycle. To study the effect of endogenous hormone fluctuations on gene expression in the mouse mammary gland, we performed bulk RNAseq analyses of epithelial and stromal cell populations that were isolated either during puberty or at different stages of the adult virgin estrous cycle. Our data confirm prior findings that proliferative changes do not occur in every mouse in every cycle. We also show that during the estrous cycle the main gene expression changes occur in adipocytes and fibroblasts. Finally, we present a comprehensive overview of the Wnt gene expression landscape in different mammary gland cell types in pubertal and adult mice. This work contributes to understanding the effects of physiological hormone fluctuations and locally produced signaling molecules on gene expression changes in the mammary gland during the reproductive cycle and should be a useful resource for future studies investigating gene expression patterns in different cell types across different developmental timepoints., (© 2024. The Author(s).)

Puberty is considered a prerequisite for affecting reproductive performance and productivity. Little was known about molecular changes in pubertal goat ovaries. Therefore, we measured and performed a correlation analysis of the mRNA and proteins changes in the pre-pubertal and pubertal goat ovaries. The results showed that only six differentially expressed genes and differentially abundant proteins out of 18,139 genes and 7550 proteins quantified had significant correlations. CNTN2 and THBS1, discovered in the mRNA-mRNA interaction network, probably participated in pubertal and reproductive regulation by influencing GnRH receptor signals, follicular development, and ovulation. The predicted core transcription factors may either promote or inhibit the expression of reproductive genes and act synergistically to maintain normal reproductive function in animals. The interaction between PKM and TIMP3 with other proteins may impact animal puberty through energy metabolism and ovarian hormone secretion. Pathway enrichment analyses revealed that the co-associated key pathways between ovarian genes and proteins at puberty included calcium signalling pathway and olfactory transduction. These pathways were associated with gonadotropin-releasing hormone synthesis and secretion, signal transmission, and cell proliferation. In summary, these results enriched the potential molecules and signalling pathways that affect puberty and provided new insights for regulating and promoting the onset of puberty. SIGNIFICANCE: This study conducted the first transcriptomic and proteomic correlation analysis of pre-pubertal and pubertal goat ovaries and identified six significantly correlated molecules at both the gene and protein levels. Meanwhile, we were drawn to several molecules and signalling pathways that may play a regulatory role in the onset of puberty and reproduction by influencing reproductive-related gene expression, GnRH receptor signals, energy metabolism, ovarian hormone secretion, follicular development, and ovulation. This information contributed to identify potential biomarkers in pubertal goat ovaries, which was vital for predicting the onset of puberty and improving livestock performance., Competing Interests: Declaration of competing interest The authors declare to have no conflict of interests., (Copyright © 2023. Published by Elsevier B.V.)

Because experimental studies to determine the developmental toxicity of exposure to various substances in children are impossible, many studies use immature male rats. This study aimed to provide normative data for longitudinal bone growth with age during the puberty in male rats. In order to evaluate long bone growth and mineralization we examined bone size and bone density by dual-energy X-ray absorptiometry, analyzed histomorphometry of the growth plate, and serum hormone levels relevant to bone growth from postnatal day (PD)20 to PD60. The length and weight of long bones increased strongly by PD40, and no further increase was observed after PD50. On the other hand, tibial growth plate height decreased sharply after PD50 along with a reduction in the number of cells and columns, which was probably responsible for the absence of further lengthening of long bones. Parameters related to bone formation such as bone area ratio, and the thickness and number of trabeculae, also increased significantly between PD40 and PD50. Furthermore, serum levels of IGF-1 peaked at PD30 and testosterone increased rapidly on and after PD40, when IGF-1 levels were going down. These changes may participate in the parallel increase in mineral acquisition, as well as lengthening of long bones. Our findings provide comprehensive data for changes in bone density, histomorphometry of long bones, and hormone levels relevant to bone growth during the growth spurt. This will be useful for planning animal toxicological studies, particularly for deciding on the appropriate age of animals to use in given experiments., (© 2024. The Author(s), under exclusive licence to Japanese Association of Anatomists.)

Olfactory communication is triggered by pheromones that profoundly influence neuroendocrine responses to drive social interactions. Two principal olfactory systems process pheromones: the main and the vomeronasal or accessory system. Prolactin receptors are expressed in both systems suggesting a participation in the processing of olfactory information. We previously reported that prolactin participates in the sexual and olfactory bulb maturation of females. Therefore, we explored the expression of prolactin receptors within the olfactory bulb during sexual maturation and the direct responses of prolactin upon pheromonal exposure. Additionally, we assessed the behavioral response of adult females exposed to male sawdust after prolactin administration and the consequent activation of main and accessory olfactory bulb and their first central relays, the piriform cortex and the medial amygdala. Last, we investigated the intracellular pathway activated by prolactin within the olfactory bulb. Here, prolactin receptor expression remained constant during all maturation stages within the main olfactory bulb but decreased in adulthood in the accessory olfactory bulb. Behaviorally, females that received prolactin actively explored the male stimulus. An increased cFos activation in the amygdala and in the glomerular cells of the whole olfactory bulb was observed, but an augmented response in the mitral cells was only found within the main olfactory bulb after prolactin administration and the exposure to male stimulus. Interestingly, the ERK pathway was upregulated in the main olfactory bulb after exposure to a male stimulus. Overall, our results suggest that, in female mice, prolactin participates in the processing of chemosignals and behavioral responses by activating the main olfactory system and diminishing the classical vomeronasal response to pheromones., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Artificial insemination (AI) centres select bulls as calves according to their genetic breeding values and raise them until the first semen collection; yet, a high dropout rate of reared bulls is a problem for AI centres. Potential hormonal indicators of bull sexual maturation (cortisol, dehydroepiandrosterone (DHEA), testosterone, oestradiol, insulin-like growth factor 1 (IGF-1)) were observed and evaluated in relation to the performance parameters to perhaps identify candidate biomarkers allowing an early selection of bulls as suitable sires. Blood samples from 102 German Holstein calves at 4 ± 1, 8 ± 1 and 12 ± 2 months of age from six AI centres were analysed using validated immunoassays for cortisol, DHEA, testosterone, oestradiol and IGF-1. Semen analyses included native and thawed diluted semen. Bulls were classified at the first semen collection into groups with good versus poor performance (GP vs. LP). After 2 years, the subsequent differentiation was done in high (HPP), medium (MPP) and low performance persistency (LPP). Age at first semen collection was an important factor for sperm quality. Cortisol concentrations decreased with age, but the cortisol/DHEA ratio decreased with age only in GP bulls (p < .05). Oestradiol and testosterone concentrations both correlated with libido behaviour (p < .05). Testosterone and IGF-1 concentrations were higher at the time of first semen collection in GP bulls and increased with age (p < .05). In conclusion, testosterone and IGF-1 concentrations at first semen collection are associated with performance at first semen collection and future performance persistency, and might be useful early biomarkers for consistent sperm producing bulls on AI centres., (© 2024 The Author(s). Reproduction in Domestic Animals published by Wiley‐VCH GmbH.)

Background: It is now well known that visfatin is expressed in the testis and ovary of various animals. Visfatin is known to regulate gonadal functions such as steroidogenesis, proliferation, and apoptosis in the ovary and testis of mice. Recently, we have shown that visfatin has an inhibitory role in the infantile mice testis. It has also been shown that visfatin stimulates testicular steroidogenesis in adult rats. However, the role of visfatin during puberty has not been investigated in relation to the above-mentioned process., Objective: The objective of the present study was to examine the effect of visfatin inhibition by FK866 from PND25 to PND35 (pre-pubertal to early pubertal) in male Swiss albino mice on steroidogenesis, proliferation, and apoptosis., Methods: Sixteen mice (25 days old) were divided into two groups, one group was given normal saline and the other group was administered with an inhibitor of visfatin (FK866) at the dose of 1.5 mg/kg by intraperitoneal injection for 10 days. Histopathological and immunohistochemical analysis, western blot analysis and hormonal assay were done., Results: Visfatin inhibition resulted in increased estrogen secretion, body weight, seminiferous tubule diameter, germinal epithelium height, and proliferation along with increased expression of BCl2, casapse3, ERs and aromatase expression in the mice testis. Visfatin inhibition down-regulated the testicular visfatin expression and also decreased abundance in the adipose tissues., Conclusion: In conclusion, decreased AR expression and increased ERs expression by FK866, suggest that visfatin might have a stimulatory effect on AR signaling than ERs in the early pubertal stage of mice., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Räsänen draws a distinction between chronological age and biological age and argues that biological ageing is (sometimes) desirable. To demonstrate this, he asks us to consider the case of April, who like Karel Čapek's Elina Makropulos, has stopped biologically ageing. Unlike Makropulos, though, April's biological ageing was halted before puberty, so she will never mature into adulthood. Räsänen contends this case shows ageing can be desirable, but this equivocates between maturing and ageing. Here I argue biological ageing, or the wear and tear normally associated with chronological ageing, is prima facie undesirable, but that maturing can be prima facie desirable., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

The study aimed to investigate the effect of Grid1, encoding the glutamate ionotropic receptor delta type subunit 1 (GluD1), on puberty onset in female rats. Grid1 mRNA and protein expression was detected in the hypothalamus of female rats at prepuberty and puberty. The levels of Grid1 mRNA in the hypothalamus, the fluorescence intensity in the arcuate nucleus and paraventricular nucleus of the prepubertal rats was significantly lower than pubertal. Additionally, the expression of Grid1 was suppressed in primary hypothalamus cells and prepubertal rat. Finally, investigated the effect of Grid1 knockdown on puberty onset and reproductive performance. Treatment of hypothalamic neurons with LV-Grid1 decreased the level of Grid1 and Rfrp-3 (encoding RFamide-related peptide 3) mRNA expression, but increased the Gnrh (encoding gonadotropin-releasing hormone) mRNA levels. After an ICV injection, the time for the rat vaginal opening occurred earlier. Moreover, Gnrh mRNA expression was increased, whereas Rfrp-3 mRNA expression was decreased in the hypothalamus. The concentration of progesterone (P 4 ) in the serum was significantly decreased compare with control group. Ovary hematoxylin-eosin staining revealed that the LV-Grid1 group mainly contained primary and secondary follicles. The reproductive performance of the rats was not affected by the Grid1 knockdown. Therefore, Grid1 may affect the onset of puberty in female rats by regulating the levels of Gnrh, and Rfrp-3 in the hypothalamus, as well as the concentrations of P 4 , but not reproduction performance.

Context: Reliable estradiol (E2) reference intervals (RIs) are crucial in pediatric endocrinology., Objectives: This study aims to develop a sensitive ultra-performance liquid chromatographic tandem mass spectrometry (UPLC-MS/MS) method for E2 in serum, to establish graphically represented RI percentiles and annual RIs for both sexes, and to perform a systematic literature comparison., Methods: First, a UPLC-MS/MS method for E2 was developed. Second, graphically represented RI percentiles and annual RIs covering 0-18 years were computed (cohort of healthy children [1181 girls and 543 boys]). Subsequently, RIs were compared with published data by systematic searches., Results: Lower limit of quantification was 11 pmol/L, indicating high sensitivity. Estradiol first peaked during mini-puberty in both sexes (girls up to 192 pmol/L; boys up to 225 pmol/L). As could be expected, girls showed higher pubertal E2 (up to 638 pmol/L). However, boys' RIs (up to 259 pmol/L) overlapped considerably. We found 4 studies in the literature that also used LC-MS/MS to determine E2 and published RIs for the complete pediatric age range. Reference intervals varied considerably. Pre-pubertal and pubertal phases were present in all studies. Higher E2 during the time of mini-puberty in both sexes was documented in 3 studies including ours., Conclusions: Variability of RIs for E2 between studies illustrates the importance of laboratory-specific RIs despite using a LC-MS/MS reference method. In boys, the striking E2 peak during mini-puberty as well as high pubertal E2 without phenotypic estrogenization in regular male puberty indicates that the role of E2 in children and, especially in boys, requires better functional understanding., Competing Interests: Conflict of interest: The authors have nothing to declare., (© The Author(s) 2024. Published by Oxford University Press on behalf of European Society of Endocrinology.)

Recent evidence indicates that sex-based differences in cardiovascular disease (CVD) begin early in life, particularly when associated with risk factors such as a sedentary lifestyle. CVD is associated with elevated sympathetic nerve activity (SNA), quantified as increased SNA burst activity in humans. Whether burst characteristics are influenced by sex or sedentary conditions at younger ages is unknown. The purpose of our study is to compare SNA bursts in active and sedentary female and male rats at ages including prepuberty and young adulthood. We hypothesized that burst characteristics and blood pressure are higher under sedentary conditions and lower in female rats compared with males. We analyzed splanchnic SNA (SpSNA) recordings from Inactin-anesthetized male and female rats at 4-, 8-, and 16-wk of age. Physically active and sedentary rats were each housed in separate, environmentally controlled chambers where physically active rats had free access to an in-cage running wheel. Sympathetic bursts were obtained by rectifying and integrating the raw SpSNA signal. Burst frequency, burst height, and burst width were calculated using the Peak Parameters extension in LabChart. Our results showed that sedentary conditions produced a greater burst width in 8- and 16-wk-old rats compared with 4-wk-old rats in both males and females ( P < 0.001 for both). Burst frequency and incidence were both higher in 16-wk-old males compared with 16-wk-old females ( P < 0.001 for both). Our results suggest that there are sedentary lifestyle- and sex-related mechanisms that impact sympathetic regulation of blood pressure at ages that range from prepuberty into young adulthood. NEW & NOTEWORTHY The mechanisms of decreased incidence of cardiovascular disease (CVD) in reproductive-age women compared with age-matched men are unknown. The strong association between elevated sympathetic activity and CVD led us to characterize splanchnic sympathetic bursts in female and male rats. Prepubescent males and females exhibited narrower sympathetic bursts, whereas young adult males had higher resting burst frequency compared with age-matched females. Sex-based regulation of sympathetic activity suggests a need for sex-dependent therapeutic strategies to combat CVD.

Life-history traits, such as size-at-maturity, are key parameters to model population dynamics used to inform fisheries management. Fishery-induced evolution, density-dependent effects, and global warming have been shown to affect size- and age-at-maturity, and resulting spawning stock biomass (SSB) in a wide range of commercial fish stocks. Marked changes in redfish biomass and environmental conditions in the Gulf of St. Lawrence and Laurentian Channel over the past decade called for a review and update of size-at-maturity for commercially important deepwater redfish Sebastes mentella and Acadian redfish Sebastes fasciatus stocks. Following a 25-year moratorium, local redfish biomass has recently reached unprecedented levels, co-occurring with an overall warming of bottom water temperatures. Our objectives were (1) to perform a histological assessment of redfish reproduction stages, including the validation and fine-tuning of a robust visual chart to facilitate monitoring of size-at-maturity and SSB in a transforming environment, and (2) to evaluate changes in size-at-maturity in unprecedentedly strong cohorts of redfish, and consequences for stock status assessment and fisheries management. Each specimen was genetically identified to species, and gonad reproduction stages were determined by histology and macroscopic appearances. The present study enabled a robust visual chart for continued and cost-effective monitoring of redfish reproduction stages to be refined and validated, and has shown a large decrease in redfish length when 50% of the individuals are considered mature that led to an increase in estimates of SSB during the 2011-2021 period for S. mentella and S. fasciatus. These changes modified the perception of stock status, thus having significant implications for fisheries management. Given that fishery-induced evolution and community structure changes along with global warming are affecting numerous stocks worldwide, the present study outlines a major and global challenge for scientists and resources managers. As shown by our results, the monitoring and frequent updates of life-history traits in transforming environments are needed to provide reliable science advice for sustainable fisheries., (© 2024 His Majesty the King in Right of Canada. Journal of Fish Biology published by John Wiley & Sons Ltd on behalf of Fisheries Society of the British Isles. Reproduced with the permission of the Minister of Fisheries Society of the British Isles.)

This study unravels the intricate interplay between photoperiod, melatonin, and kisspeptin to orchestrate the pubertal onset of Common carp. Female fingerlings exposed to long days (LD) exhibited a hormonal crescendo, with upregulated hypothalamic-pituitary-ovarian (HPO) axis genes (kiss1, kiss1r, kiss2, gnrh2, gnrh3) and their downstream targets (lhr, fshr, ar1, esr1). However, the expression of the melatonin receptor (mtnr1a) diminished in LD, suggesting a potential inhibitory role. This hormonal symphony was further amplified by increased activity of key transcriptional regulators (gata1, gata2, cdx1, sp1, n-myc, hoxc8, plc, tac3, tacr3) and decreased expression of delayed puberty genes (mkrn1, dlk1). In contrast, short days (SD) muted this hormonal chorus, with decreased gnrh gene and regulator expression, elevated mtnr1a, and suppressed gonadal development. In in-vitro, estradiol mimicked the LD effect, boosting gnrh and regulator genes while dampening mtnr1a and melatonin-responsive genes. Conversely, melatonin acted as a conductor, downregulating gnrh and regulator genes and amplifying mtnr1a. Our findings illuminate the crucial roles of melatonin and kisspeptin as opposing forces in regulating pubertal timing. LD-induced melatonin suppression allows the kisspeptin symphony to flourish, triggering GnRH release and, ultimately, gonadal maturation. This delicate dance between photoperiod, melatonin, and kisspeptin orchestrates common carp's transition from juvenile to reproductive life., (© 2024 Wiley Periodicals LLC.)

The purpose of this study was to analyse secular trend in handgrip strength (HGS) in adolescents using an allometric approach and identify the factors associated. The sample comprised 657 and 1004 adolescents (14 to 19 years) in 2007 and 2017/2018, respectively, of public schools in Florianópolis, Brazil. The dependent variable was HGS normalised to body mass and height. Covariance analysis was used to examine secular trends in HGS, and multiple linear regression was used to identify associated factors. The independent variables were sociodemographic, biological, and behavioural factors. Comparison of HGS between surveys indicated a negative secular trend in both sexes ( p  < 0.001). In boys, there was a positive association of HGS with age and FFM in both surveys. In 2017/18, there was a positive association with sexual maturation and a negative association with sitting time and fat percentage. In girls, FFM was positively associated with HGS in both surveys. In 2007, there were positive associations of HGS with age and vigorous physical activity, whereas, in 2017/18, negative associations were observed with economic level and sitting time. The findings of the present study show a decline in adolescent HGS. And behavioural changes appear to be contributing to declines in HGS.

Importance: Earlier puberty is associated with adverse health outcomes, such as mental health issues in adolescence and cardiometabolic diseases in adulthood. Despite rapid growth of the Asian American, Native Hawaiian, and Pacific Islander populations in the US, limited research exists on their pubertal timing, potentially masking health disparities., Objective: To examine pubertal timing among Asian American, Native Hawaiian, and Pacific Islander children and adolescents by disaggregating ethnic subgroups., Design, Setting, and Participants: This retrospective cohort study included Asian American, Native Hawaiian, and Pacific Islander youths aged 5 to 18 years assessed for pubertal development at Kaiser Permanente Northern California, a large, integrated health care delivery system. Follow-up occurred from March 2005, through December 31, 2019. Data were analyzed in October 2023., Exposure: Race and ethnicity, categorized into 11 ethnic subgroups: Asian Indian, Chinese, Filipino, Japanese, Korean, Native Hawaiian and Pacific Islander, Other South Asian, Other Southeast Asian, Vietnamese, multiethnic, and multiracial., Main Outcomes and Measures: Pubertal timing was determined using physician-assessed sexual maturity ratings (SMRs). Outcomes included the median age at transition from SMR 1 (prepubertal) to SMR 2 or higher (pubertal) for onset of genital development (gonadarche) in boys, breast development (thelarche) in girls, and pubic hair development (pubarche) in both boys and girls., Results: In this cohort of 107 325 Asian American, Native Hawaiian, and Pacific Islander children and adolescents (54.61% boys; 12.96% Asian Indian, 22.24% Chinese, 26.46% Filipino, 1.80% Japanese, 1.66% Korean, 1.96% Native Hawaiian and Pacific Islander, 0.86% Other South Asian, 3.26% Other Southeast Asian, 5.99% Vietnamese, 0.74% multiethnic, and 22.05% multiracial), the overall median ages for girls' pubarche and thelarche were 10.98 years (95% CI, 10.96-11.01 years) and 10.13 years (95% CI, 10.11-10.15 years), respectively. For boys' pubarche and gonadarche, median ages were 12.08 years (95% CI, 12.06-12.10 years) and 11.54 years (95% CI, 11.52-11.56 years), respectively. Differences between subgroups with earliest and latest median age at onset were 14 months for girls' pubarche, 8 months for thelarche, 8 months for boys' pubarche, and 4 months for gonadarche. In general, Asian Indian, Native Hawaiian and Pacific Islander, and Other South Asian subgroups had the earliest ages at onset across pubertal markers, while East Asian youths exhibited the latest onset. Restricting to those with healthy body mass index did not substantially change the findings., Conclusions and Relevance: In this cohort study of Asian American, Native Hawaiian, and Pacific Islander children and adolescents, pubertal timing varied considerably across ethnic subgroups. Further investigation is warranted to assess whether these differences contribute to observed health disparities in adulthood, such as type 2 diabetes and cardiovascular diseases.