Variations of gossypol susceptibility in rat spermatozoa during spermatogenesis.

Sperm collected at two epididymal regions from various rat groups force-fed with gossypol were assayed for their ATP levels and motilities to examine their response to the antifertility effect of gossypol, a yellowish polyphenolic pigment from cottonseed oil. Rats receiving gossypol administration for 2 weeks began to show a proportional decrease in spermatozoal ATP content and motility and this antifertility effect deepened with time. Recovery from the gossypol-induced ATP decrease also developed at 2 weeks after the removal of gossypol administration. This rapid development of both the inhibitory and the recovery effects in a normal 53-day spermatogenic process might have stemmed from a change of susceptibility to gossypol inhibition during spermatogenesis. A model showing a more susceptible middle stage in spermatogenesis is proposed.