Effect of gossypol on the motility and metabolism of human spermatozoa.

Gossypol, a polycyclic compound isolated from cotton seeds, had a dose-dependent inhibitory effect on human sperm motility. The drug also inhibited powerfully fructolysis and glycolysis by human spermatozoa. Both lactate and CO2 formation from the 14C-labelled sugars was inhibited, and the prevention of CO2 formation from [1-14C]pyruvate and [2-14C]pyruvate by gossypol indicated a direct effect on the tricarboxylic acid cycle. Repeated washing of the sperm cells after gossypol pretreatment failed to abolish the inhibitory effect on CO2 production. The profound disturbances of the sperm energy metabolism induced by gossypol were also reflected by a striking fall of the sperm ATP content. Gossypol had little effect on glucose utilization by minces of human vaginal mucosa, indicating the specificity of gossypol.