Gossypol inhibits testicular steroidogenesis.

Gossypol, a compound isolated from cottonseed, has been used in the People's Republic of China as an antifertility agent in men. It was reported that gossypol is highly effective in reducing sperm count. Our study suggests that gossypol inhibits luteinizing hormone, 8-bromo-adenosine 3',5'-monophosphate-induced testosterone formation, and the conversion of pregnenolone to testosterone in isolated rat interstitial cells. Serum testosterone levels were also significantly reduced in rats after 1 week of treatment with gossypol. Oligospermia and azoospermia in men caused by gossypol may be secondary to decreased testosterone biosynthesis.