EFFECT OF VISFATIN ON TESTICULAR STEROIDOGENESIS IN PURIFIED LEYDIG CELLS
AbstractBackground: Lower testosterone levels have been reported in men suffering from diabetes mellitus.Men with insulin resistance states such as obesity and type 2 diabetes mellitus have significantly lowertestosterone levels than age-matched normal weight and non-diabetic controls. Adipose tissue secretesvariety of adipokinesincluding adiponectin, resistin, visfatin, TNF-α. The study was designed to studythe effect of visfatin on testicular steroidogenesis in purified Leydig cell in vitro. Methods: Leydigcells of Sprague Dawley rats were isolated and purified by Percoll. Cells were incubated for 3 hourswith/without visfatin in the presence/absence of LH and intracellular signalling blockers including PKCblocker, PKA blocker and Raf1/Ras blocker. Cell culture extracts were stored at -80 ℃ before analysisfor levels of testosterone hormone by ELISA. Results: Visfatin increased testosterone production(p<0.001) from cultured Leydig cells. Raf1/Ras blocker decreased visfatin induced steroidogenesis(p<0.001). Conclusion: Visfatin increased testicular steroidogenesis from Leydig cells in vitro modelsand operates through variety of enzymes, but especially through Ras/Raf1 kinase enzymes.Keywords: Visfatin, adipocytokines, Leydig cells, testicular steroidogenesis
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