Effect of gossypol on bull spermatozoa in vitro.

Gossypol acetic acid in a concentration of 1,000 microgram/ml solvent is able to immobilize 1 ml of native bull semen (sperm concentration: 8.5 X 10(8)/ml; motility rate: 87.4%) within 30 min. After GAA treatment the spermatozoa show severe morphological damage on the membrane system, on the acrosomal complex and on the tubular complex of the end piece. The working mechanism of GAA can be assumed to be inactivation of enzyme activities or in direct reactions with plasma membrane material.