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Introduction: Orexin-A is a neuropeptide synthesized in the lateral hypothalamus. Orexin-A immunoreactive fibres overlap distribution with GnRH neurons. In adult rats, orexin A is known to affect LH secretion via GnRH release modulation. Because data concerning the impact of orexin-A on the hypothalamo-pituitary axis activity are limited, we focused on the involvement of orexin-A and receptors of NPY in the modulation of LH release and LH subunit b (Lhb) mRNA expression in prepubertal female rats., Material and Methods: Forty immature female Wistar rats were divided into 4 groups and received 2 intracerebroventricular (icv) microinjections of: 1 - artificial cerebrospinal fluid (CSF) (controls); 2 - CSF followed by orexin A; 3 - selective NPY receptor antagonist (BIBP) followed by CSF; 4 - BIBP followed by orexin A. One hour after the last microinjection, all rats were decapitated. Trunk blood was collected, and serum was stored at -20°C for the LH RIA examination. The adenohypophysis was immediately excised, flash-frozen, and kept at -80°C for RNA extraction. Real-time PCR amplification was carried out, and relative Lhb gene expression was calculated., Results: In comparison to the CSF-treated controls with a mean LH serum concentration of 0.40 ± 0.02 ng/mL, the mean LH serum level was diminished both after orexin-A (0.27 ± 0.01 ng/mL) and after BIBP (0.30 ± 0.02 ng/mL) icv microinjections. In the presence of BIBP, orexin-A more effectively inhibited LH release (0.20 ± 0.01 ng/mL) when compared to the BIBP-treated group. Orexin-A and BIBP exerted a consistent inhibitory effect on Lhb mRNA expression levels in the anterior pituitary gland. In comparison to the CSF-treated controls, orexin-A, and BIBP-treated females responded with, respectively, 35% and 40% reduction of Lhb mRNA expression. Orexin-A and BIBP co-administration evoked a further reduction of Lhb gene transcriptional activity., Conclusions: Orexin-A exerts a down-regulatory effect on LH synthesis and release in immature female rats. Considering that Y1R-oriented down-regulation of endogenous NPY activity did not reverse the suppressive effect of exogenous orexin-A, it might be suggested that NPY and orexin A systems can operate independently to affect gonadotropin activity in the anterior pituitary of the immature female rats.

Introduction: Multiple sclerosis (MS) is an autoimmune disease of the central nervous system. The exact aetiology is unknown. However, genetic and environmental factors are suggested to be involved in the pathogenesis of MS. Improper diet, resulting in obesity and metabolic syndrome, can contribute to this disease. Adipokines, secreted by adipose tissue, link the metabolism and immune system., Material and Methods: We aimed to assess plasma levels of selected adipokines in newly diagnosed, treatment-naïve individuals with multiple sclerosis. Our group comprised 58 individuals (31 MS patients and 27 controls, matched for age and BMI) without diabetes, hypertension, or dyslipidaemia. Circulating adiponectin and all adiponectin fractions, visfatin, and omentin concentrations were measured. Metabolic parameters were also assessed., Results: In MS individuals we observed the following results: higher concentrations of visfatin, lower levels of omentin, and no differences in adiponectin array. There were also correlations between some adipokines and metabolic parameters. After adjustment to BMI, a significant decrease in total adiponectin, high-molecular weight (HMW) adiponectin and omentin, and an increase in medium-molecular-weight (MMW) adiponectin were observed in the group of MS patients when compared to those of the controls., Conclusions: Our results indicate that adiponectin with its fractions, visfatin, and omentin cannot be considered as causative factors in the early phase of multiple sclerosis. However, the potential role of adipokines in MS is possible because they might be involved in the pathogenesis of MS, regarded as an autoimmune disorder.

Introduction: Anorexia nervosa (AN) is an eating disorder characterised with extremely low weight. Adipokines are adipose tissue-derived substances that show a wide spectrum of biological activities. We aimed to assess selected adipokine levels in women with AN before and after nutritional intervention. We also sought to examine whether BMI is the only confounding factor influencing adipokine assessment in AN., Material and Methods: Sixty-five women participated in the study: 20 individuals with AN before any treatment, 18 AN patients after nutritional intervention lasting for at least six months, and 27 women as controls. In all participants blood collection and anthropometric measurements were performed. ELISA was used for evaluation of leptin receptor, adiponectin and its isoforms, and resistin. Leptin was assessed with RIA, and visfatin was measured with EIA assay., Results: Leptin and free leptin index (FLI) were lowest in treatment-naïve AN women. HMW-adiponectin and visfatin were enhanced in AN. Other adipokine levels showed no significant differences. When two subsets of anorexia nervosa were compared, only leptin, leptin receptor, and FLI were markedly different. When data were adjusted to BMI, leptin and FLI remained significantly different in the pre-treated AN subgroup when compared with the control group., Conclusions: Our results suggest that leptin is the most important adipokine in AN. It is also important that in our AN population leptin and FLI are the only factors that are influenced not only by the fat content.