Rouleau formation and fertility of spermatozoa in guinea pigs treated with cyproterone acetate.

The effects of cyproterone acetate (CA) on fertility of spermatozoa and rouleau formation were investigated in male guinea pigs. Twelve of 15 matings during CA treatment resulted in pregnancy even when rouleaux were absent in ejaculates, indicating that the rouleau condition is not necessary for the fertilizing ability of guinea pig spermatozoa. Examination of epididymides and vasa deferentia revealed that rouleaux diminished progressively with treatment time and were absent in the excurrent ducts of all males during the eighth and ninth weeks of treatment. Following a latent period after treatment, rouleaux were first noted in a specific epididymal region and were present throughout the distal excurrent ducts and ejaculates by 6 wk posttreatment. This sequence of rouleau loss and reappearance in the excurrent ducts suggests that rouleau formation is dependent on a regional epididymal influence that requires androgens. Spermatogenesis was not arrested; however, seminal vesicle and body weights were reduced in treated males.