Sexual maturation in male mice treated with cyproterone acetate from birth to puberty

Cyproterone acetate was administered every 2 days from 1 to 39 days of age to male mice which were killed 24 h or 20 days after the last injection. Cyproterone acetate caused a significant reduction in the relative weights of the epididymis, vas deferens, seminal vesicle and preputial gland, which was still evident at 60 days after birth. Testicular and epididymal androgens (testosterone and dihydrotestosterone) and circulating LH and FSH concentrations were equal to or higher than those of controls at 60 days. Cyproterone acetate did not inhibit spermatogenesis but all males were infertile. The results suggest that the peripheral effects of testosterone are necessary, during early stages of sexual maturation, in order to obtain subsequent full development of the accessory sex organs.