title: Biphasic c-Myc protein expression during gossypol-induced apoptosis in rat spermatocytes.
abstract: The presence of protooncogene products such as c-Myc proteins in rat spermatocytes has been quantitatively detected by Western immunoblot and a computer-controlled Spotdenso-program with an IS-1000 digital imaging system. Cellular levels of c-Myc proteins in response to gossypol were measured in spermatocytes during the process of gossypol-induced apoptosis. Within 0.5 to 2 h of the addition of gossypol, levels of c-Myc proteins fall dramatically and remain at a low level for the next several hours. The reduction in c-Myc proteins occurs 4.5-6 h before the apoptosis of spermatocytes in the presence of gossypol. Between 3 and 5 h after exposure to gossypol, the c-Myc protein content returns to preexposure (or higher) levels. In addition, the increase in c-Myc proteins occurs 1.5-4 h before the apoptotic death of spermatocytes. An identical pattern of c-Myc protein response to gossypol was also found in total testicular tissue in vitro. These results suggest that spermatocyte apoptosis induced by gossypol is correlated with biphasic c-Myc protein expression. This article present some hypothetical models with which to explain c-Myc protein-mediated apoptosis.
authors.affiliation: Department of APR, North Carolina State University, Raleigh 27606, USA.
authors.forename: C S
authors.initials: CS
authors.lastname: Teng
authors.forename: X
authors.initials: X
authors.lastname: Vilagrasa
mesh_terms: D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D046508:Culture Techniques; D004591:Electrophoresis, Polyacrylamide Gel; D006072:Gossypol / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D013094:Spermatozoa / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism*; D013737:Testis / Q000187:drug effects / Q000378:metabolism
chemical_list: D016271:Proto-Oncogene Proteins c-myc; D006072:Gossypol