[Effects of cyclosporin A on male reproduction in rats]

Effects of cyclosporin (Cs) on male reproduction in rats were examined. A dose-dependent decrease of the sperm counts in the cauda epididymis was observed 6 weeks after Cs was administered. A significant decrease of sperm motility was also observed in the each Cs-treated group in any observational period after Cs injection, which suggested an injury to epididymis by Cs. A slight damage of the seminiferous tubules was demonstrated 6 weeks after administration of 40 or 60 mg/kg of Cs. No change in serum levels of luteinizing hormone and testosterone was demonstrated throughout the experiment. But serum levels of follicle-stimulating hormone were significant high in any observational period except 6 weeks after Cs injection. It was concluded that Cs gave injuries to both spermatogonia and epididymal function in rat.