Effect of cyproterone acetate on steroid-induced sexual behavior in adult ewes

The inhibitory effect of cyproterone acetate on sexual behavior has been investigated in adult ovariectomized ewes treated with either testosterone propionate (10 mg/day) or estradiol benzoate (200 micrograms/day) to induce male activity and female receptivity simultaneously. Intra-muscular injections of 100 mg cyproterone acetate/day resulted in a rapid decrease in some of the male sexual responses after both testosterone and estradiol treatments, whereas the female reactions were eliminated by cyproterone acetate only when they had been induced by testosterone.