Site of gossypol inhibition of steroidogenesis in purified mouse Leydig cells.

Gossypol, a phenolic compound that has been studied as a potential male contraceptive, inhibits basal and LH-stimulated testosterone release from Leydig cells in vitro. The present study investigates the mechanism of this inhibition using preparations of purified mouse Leydig cells. Gossypol inhibited LH-stimulated progesterone, 17-hydroxyprogesterone and androstenedione production by mouse Leydig cells incubated in vitro. It also inhibited dibutyryl cyclic AMP-stimulated production of testosterone but was without effect in the presence of added pregnenolone or 25-hydroxycholesterol. These results suggest gossypol exerts its major inhibitory effect on Leydig cell function at a point between LH-dependent stimulation of cyclic AMP dependent protein kinase activity and increased availability of cholesterol for side chain cleavage.