Mechanism of inhibition by gossypol of glycolysis and motility of monkey spermatozoa in vitro.

Low levels of gossypol inhibited motility and anaerobic glycolysis of ejaculated rhesus monkey spermatozoa. Inhibition (50%) of both occurred at a gossypol: sperm ratio of 8 nmol/10(8) spermatozoa, and complete inhibition of both occurred at a ratio of 75 nmol/10(8) spermatozoa. Determination and comparison of the levels of glycolytic intermediates in intact spermatozoa, incubated with and without gossypol, indicated that the only site of glycolytic inhibition was lactate dehydrogenase-X (EC 1 X 1 X 1 X 27). At gossypol: sperm ratios above 6 nmol/10(8) spermatozoa, gossypol also decreased the concentrations of the adenine nucleotides, ATP, ADP and AMP, and this is most probably the basis for its toxic effect on spermatozoa.