Background: Chemerin is an adipocytokine that controls adipocyte differentiation and related to immune and inflammatory functions. Post-menopausal osteoporosis (PMOP) is the most common bone disease in females characterized by decreased bone mineral density (BMD); relationship between chemerin and osteoporosis remains unclear. Objective: To assess serum chemerin levels in osteoporotic rat model induced by ovariectomy, and to investigate the interplay between serum chemerin levels and BMD, also the impact of estradiol replacement therapy on chemerin levels and its association with BMD parameters. Material and methods: Three equal groups of adult female albino rats (n=12) were used; sham operated control (sham), ovariectomized (OVX) and OVX with estrogen replacement (OVX-ER) groups. Nine weeks after ovariectomy, serum analysis, bone BMD measurements and histopathology were done. Results: In OVX osteoporotic rat model, serum levels of chemerin were significantly elevated (P<0.001) when compared to other groups, and negatively correlated with BMD, Changes in OVX chemerin levels were significantly associated with the elevated insulin resistance. However, they were not associated with FSH or estradiol levels. Conclusion: OVX induced osteoporosis was associated with significant rising in chemerin levels which were associated with changes in insulin resistance rather than sex hormones. It can be hypothesized that the exact causative of PMOP extends beyond pituitary; ovarian axis to be metabolic and adiposity cross talks which needs more detailed investigations.

Introduction:Cognitive impairment and glucose intolerance are prevalent in obese subjects. Irisin, a recently identified modifier of cognitive functions and glucose metabolism, was reported to be induced by physical exercise. We examined the association of exerciseinduced irisin levels with improved cognitive functions and glucose metabolism in both obese and normal weight subjects. Subjects and Methods: 120 subjects, both males and females, comprised of 60 obese and 60 normal-weight subjects were undergone supervised active aerobic exercises for 3-months. Irisin levels, cognitive functions, fasting blood glucose, insulin, homeostatic model assessment of insulin resistance index (HOMA-IR) were assessed at the initiation and termination of the study. Results: Obese subjects demonstrated lower irisin levels, impaired cognitive functions and higher insulin as well as HOMA-IR levels compared to the normal weight group. Physical exercise induced significant upregulation of irisin levels together with improvement of cognitive functions and significant reduction of insulin and HOMA-IR levels in both groups. Exercise-induced irisin levels demonstrated significant positive correlations with improved cognitive functions and significant negative correlation with insulin level and HOMA-IR. Conclusion: Physical exercise improves cognitive functions and glucose metabolism. Our results suggest that irisin could be an important molecular mediator and therapeutic target for improving cognitive functions and glucose metabolism.