Search

Purpose: The purpose of this study was to investigate whether a treadmill endurance exercise program would reduce serum testosterone and leptin in male rats and assess the impact of increased dietary cholesterol on serum hormones.Methods: Male Sprague-Dawley Rats (n = 20) were randomly assigned to a control group (C) or an exercise training group (EX) that performed treadmill running 40 min/day, 6 days/week for 12 weeks. At study midpoint (week 6), rats were randomized to a high-cholesterol (HC) diet (n = 10) or remain on standard semi-purified (LC) diet (n = 10).Results: Results are presented as median [IQR]. At end of week 6, EX + LC had significantly lower body weight (508 [460-527] vs 570 [516-606] g; p = 0.01), mean daily energy intake (76.3 [74.9-82.2] vs 90.9 [86.9-94.5] kcal; p < 0.01), and serum leptin (0.4 [0.3-0.6] vs 3.3 [2.0-4.0] ng/mL; p < 0.01) in comparison to C + LC. No difference was observed between EX + LC and C + LC in serum testosterone (12.6 [6.9-18.3] vs 11.7 [7.6-18.9] ng/mL). At end of week 12, EX + LC had significantly lower body weight (514 [483-568] g) compared to C + LC (644 [575-680] g; p < 0.01) and C + HC (650 [583-702] g; p < 0.01). Serum Leptin in both EX + LC (0.6 [0.2-0.8] ng/mL) and EX + HC (0.6 [0.3-1.6] ng/mL) was significantly lower than C + LC (3.0 [2.2-4.2] ng/mL; p < 0.01). No significant difference in testosterone was observed between C + LC and C + HC (4.3 [3.3-8.3] vs 6.3 [3.2-9.3] ng/mL, respectively).Conclusions: Despite lower energy availability, exercise-induced changes in sex hormones may not occur in training programs ≤ 12 weeks. Lower voluntary energy intake observed in exercise groups despite greater energy expenditure may indicate that lower energy availability in endurance-trained individuals may be inadvertent. [ABSTRACT FROM AUTHOR]

Homozygosity for the common ACTN3 null polymorphism (ACTN3 577X) results in α-actinin-3 deficiency in ~20% of humans worldwide and is linked to reduced sprint and power performance in both elite athletes and the general population. α-Actinin-3 deficiency is also associated with reduced muscle mass, increased risk of sarcopenia, and altered muscle wasting response induced by denervation and immobilization. Here, we show that α-actinin-3 plays a key role in the regulation of protein synthesis and breakdown signaling in skeletal muscle and influences muscle mass from early postnatal development. We also show that α-actinin-3 deficiency reduces the atrophic and anti-inflammatory response to the glucocorticoid dexamethasone in muscle and protects against dexamethasone-induced muscle wasting in female but not male mice. The effects of α-actinin-3 deficiency on muscle mass regulation and response to muscle wasting provide an additional mechanistic explanation for the positive selection of the ACTN3 577X allele in recent human history. [ABSTRACT FROM AUTHOR]

Background: Human fertility has always been a topic of curiosity and devotion. Many cultures consider fertility to be a necessity for the survival and perpetuation of mankind and since early times, myths were created to explain this fabulous process. Fertility gods were ubiquitous in numerous ancient human cultures and were used both to understand fertility and to cope with infertility by means of rituals and offerings. Objectives: This manuscript aims to catalog and describe the deities associated with male fertility and virility. Material and methods: We conducted a comprehensive search for the terms "male fertility god" and "male virility god" on the internet using web‐based search engines. Based on the information retrieved, we selected those deities directed related to male fertility and/or virility and further deepened the search using Pubmed and Medline databases for peer‐reviewed articles as well as books and articles about ancient mythology. Results: We identified several gods linked to male fertility and virility in various cultures from Egypt, Greece, Rome, India, Southwestern United States, France, Colombia and Buthan.. Discussion: Most of these deities were depicted with an erect phallus and with other fertility symbols like snakes. Some deities were also associated with plants and/or animal fertility and their festivals were often held during the harvest period. Conclusion: Gods of male fertility and virility played important roles in many ancient cultures. Offerings and rituals to these gods were the only available options to deal with problems of reproduction and demonstrate the lengths to which ancient people would go seeking cures for infertility. [ABSTRACT FROM AUTHOR]

Loss of expression of ACTN3 , due to homozygosity of the common null polymorphism (p.Arg577X), is underrepresented in elite sprint/power athletes and has been associated with reduced muscle mass and strength in humans and mice. To investigate ACTN3 gene dosage in performance and whether expression could enhance muscle force, we performed meta-analysis and expression studies. Our general meta-analysis using a Bayesian random effects model in elite sprint/power athlete cohorts demonstrated a consistent homozygous-group effect across studies (per allele OR = 1.4, 95% CI 1.3–1.6) but substantial heterogeneity in heterozygotes. In mouse muscle, rAAV-mediated gene transfer overexpressed and rescued α-actinin-3 expression. Contrary to expectation, in vivo “doping” of ACTN3 at low to moderate doses demonstrated an absence of any change in function. At high doses, ACTN3 is toxic and detrimental to force generation, to demonstrate gene doping with supposedly performance-enhancing isoforms of sarcomeric proteins can be detrimental for muscle function. Restoration of α-actinin-3 did not enhance muscle mass but highlighted the primary role of α-actinin-3 in modulating muscle metabolism with altered fatiguability. This is the first study to express a Z-disk protein in healthy skeletal muscle and measure the in vivo effect. The sensitive balance of the sarcomeric proteins and muscle function has relevant implications in areas of gene doping in performance and therapy for neuromuscular disease. [ABSTRACT FROM AUTHOR]

The coupling between different types of surface (tropical forest or grass) and the Convective Boundary Layer (CBL) has been investigated using observational (rawinsoundings) data collected over Rondônia in southwest Amazonia. The data reported here support the notion that deforestation may modify the dynamics of the boundary layer, in particular during the dry season. In this period the sensible heat fluxes are very high over pasture, creating a CBL around 550m deeper compared to that over the forest. The measurements showed the height of the fully developed CBL for pasture to be 1650 m, compared to around 1100m for forest. During the wet season the height of the CBL is lower than during the dry season and has the same height (around 1000 m) for forest and pasture sites. The CBL over pasture is hotter and drier than over forest during the dry season, but during the wet season the air temperatures and humidities are similar. Comparing the CBL growth during the dry and wet season, there is evidence that the CBL properties over the forest are not dependent on the surface characteristics, but over the pasture they are. [ABSTRACT FROM AUTHOR]