Reversible changes in the content of cellular and microtubular tubulin in spermatogenic cells after gossypol treatment.

After exposure of young male rats to gossypol acetic acid for various times, a reduction in the content of cellular and microtubular beta-tubulin was found in spermatocytes and spermatids. The content of tubulin was measured by enzyme-linked immunosorbent assay (ELISA). The results were expressed as micrograms tubulin/100 micrograms total protein and compared with those of the control rats. After drug treatment for 2, 6, 12, and 20 weeks, the content of total cell tubulin in spermatocyte was reduced by 2.4%, 8.8%, 52%, and 61%, respectively; whereas the content of tubulin in spermatid was reduced by 7.4%, 36%, 70%, and 72%, respectively. At the same time length of drug treatment, the content of microtubular tubulin in spermatocyte was reduced by 1.6%, 13%, 58%, and 61% in comparison to the reduction rate of 5%, 37%, 69%, and 77%, respectively, for spermatid. These results indicated that the tubulins associated with spermatids were more vulnerable to gossypol than that of the spermatocytes. Eight weeks after withdrawal of the drug treatment, the content of tubulin in spermatocytes and spermatids was recovered.