Effect of alpha-blockers on epididymal sperm concentration, motility and testicular productivity in the rat.

The present study was undertaken to determine whether alpha-blockers affect epididymal sperm parameters and testicular spermatogenesis. Sprague-Dawley rats were given orally a 1 mg/kg body weight dose of Bunazosin, a selective alpha-adrenoreceptor antagonist, daily for one month as a short-term administration group and three months as a long-term administration group. Using a micropuncture technique, epididymal sperm concentration and sperm motility were measured. Epididymal sperm concentrations were significantly increased in the Bunazosin group, but progressive motility of spermatozoa were not altered. Daily testicular sperm production was also increased after administration of Bunazosin. There were no differences in epididymal sperm concentration and daily sperm production between the one-month group and three-month group. An epididymal wide storage capacity and short transit time after administration of the alpha-blocker could increase the sperm concentration in the cauda epididymidis. Because there were no differences in the epididymal sperm parameters and daily testicular sperm production between the two groups, these changes may occur at 1 month after administration of the alpha-blocker. Moreover, the alpha-blocker might affect testicular function.