Sites of action of gossypol studied by autoradiography and enzyme histochemistry.

The distribution of 14C-gossypol acetate was studied by autoradiography in male rats after intraperitoneal or intratesticular injection. Accumulation of radioactivity was found in testis, kidney and liver, while there was little in brain, pituitary and epididymis. In testis, high accumulation occurred in interstitial cells, with low levels in Sertoli cells, spermatogonia and spermatocytes. In addition, the chronic effect of gossypol was assessed by enzyme histochemistry with thiamine pyrophosphate, alpha-glycerophosphate dehydrogenase, and by lipid stain. In the treated animals an increased number of luminal exfoliated cells (Sertoli cells, germ cells and spermatids) was noted, which showed positive reactions. The results suggest both direct and indirect effects of gossypol on testicular functions.