Inhibition by (+) and (-) isomers of gossypol of testosterone release from mouse Leydig cells in vitro.

Racemic (+/-) mixtures of gossypol isomers exert an antifertility effect by inhibiting sperm motility and spermatogenesis. Purified (+) gossypol has been shown to be without these actions. In this study pure preparations of both (+) and (-) gossypol were found to inhibit, in a similar manner, both basal and LH-stimulated release of testosterone by isolated Leydig cells at concentrations down to 21 microM. It is possible that use of low doses of pure (-) gossypol could inhibit fertility with less endocrine side effects.