Testosterone suppresses spermatogenesis in juvenile spermatogonial depletion (jsd) mice

Male juvenile spermatogonial depletion (jsd/jsd) mice are sterile because o f a failure of spermatogonial differentiation. We have previously reported the recovery of spermatogonial differentiation by suppressing the levels of gonadotropins and testosterone with Nal-Glu, a GnRH antagonist. To determi ne whether suppression of testosterone or the gonadotropins was responsible for spermatogenic recovery, we examined the effect of supplementation of L H or FSH along with Nal-Glu treatment. Systemic administration of flutamide , an androgen receptor antagonist, was also examined. LH supplementation el evated both serum and intratesticular testosterone levels and suppressed th e recovery of spermatogonial differentiation in a dose-dependent manner. Su pplementation with FSH did not affect either testosterone levels or spermat ogonial differentiation. Furthermore, the mice treated with flutamide showe d some recovery of spermatogonial differentiation. The overall findings rev ealed that testosterone action mediated by androgen receptors suppressed th e spermatogonial differentiation in jsd/jsd mice and suggested that spermat ogonial differentiation in the jsd mutant is highly sensitive to testostero ne suppression.