C-FOS PROTEIN EXPRESSION IN APOPTOTIC RAT SPERMATOCYTES INDUCED BY GOSSYPOL

Proto-oncogene products such as c-fos protein with a molecular weight of 62 kDa have been identified in rat spermatocytes. In this study, ce llular levels of c-fos proteins in spermatocytes, either with or witho ut gossypol exposure, were quantitatively detected by Western immunobl ot and a computer-controlled Spot-denso-program with an IS-1000 Digita l Imaging System. Within 0.5-3.5 h (an average of 2 h) of the addition of gossypol, levels of c-fos proteins fell dramatically. The reductio n in c-fos proteins occurred G h before the apoptosis of spermatocytes in the presence of gossypol. Four hours after exposure to gossypol, t he c-fos protein content was overexpressed. The period of c-fos up-reg ulation lasted for approximately 8 h. The increase in c-fos protein co incided with a high rate of apoptotic cell death, Morphologic structur e of the dying cell was revealed by electron microscopy. These results suggest that spermatocyte apoptosis induced by gossypol correlates wi th biphasic c-fos protein-mediated apoptosis. CONTRACEPTION 1998;57:28 1-286 (C) 1998 Elsevier Science Inc. All rights reserved.