Effect of tamoxifen treatment on motility related proteins in rat spermatozoa.

The study was undertaken to identify the effect of tamoxifen on the expression and phosphorylation of motility related proteins in the adult male rats. For this purpose, tamoxifen, at a dose of 0.4 mg/kg/day, was administered per os to the male rats for a period of 60 days. Cauda sperms, epididymal fluid and tissue proteins were extracted and analyzed by electrophoresis. Testicular tissues fixed in paraffin wax were analyzed for changes in the immunoexpression of interstitial tissue estrogen receptor alpha. Phosphorylation pattern of sperm proteins was studied in vitro after incubating with 32P-ATP. The expression of dynein and tubulin in sperms, and estrogen receptors in epididymis were analyzed by immunoblotting. Tamoxifen treatment did not alter the protein profile in the cauda sperms, epididymal fluid and tissues. Endogenous phosphorylation pattern of sperm proteins in vitro was also not affected, though it is possible that 32P incorporation observed in the 66 kDa protein could be estrogen receptor. Expression of sperm dynein, tubulin and epididymal estrogen receptors was unchanged as was the expression of testicular estrogen receptors. It was concluded that tamoxifen administration alters forward motility pattern characteristic of cauda sperm without any demonstrable change in the expression or activation of motility related proteins and the phosphorylation of the sperm estrogen receptors may be involved in the regulation of sperm motility.