Biological activity in the repopulating rat spermatocyte after the withdrawal of gossypol treatment. V. Inhibition and recovery of microtubular dynein.

After oral administration with gossypol acetic acid for various times, young male rats developed a low content of microtubular (or cytoplasmic) dynein in the spermatogenic cells, e.g., spermatids and primary spermatocytes. The content of dynein in the cells was measured by enzyme-linked immunosorbent assay (ELISA) using monoclonal anti-dynein antibody. The results were expressed as ng dynein/10(6) cells and compared with those of the control rats. After gossypol treatment for 8, 12, and 19 weeks, the content of dynein in spermatids was reduced by 61%, 70%, and 68%, respectively; whereas, the amount of dynein in primary spermatocytes was reduced by 37%, 44%, and 31%, respectively. The microtubular dynein associated with spermatids was more vulnerable to gossypol than that of the primary spermatocytes. Immunofluorescent staining technique confirmed the finding that the control cells have more dynein than that of the drug-treated cells. Eight weeks after the withdrawal of the drug treatment, the content of dynein in spermatids and primary spermatocytes was fully recovered. The possible effects of this change in conjunction with the function of microtubules during spermatogenesis and sperm motility are discussed.