TEMPORAL CHANGES IN SULFATED GLYCOPROTEIN-2 (CLUSTERIN) AND ORNITHINEDECARBOXYLASE MESSENGER-RNA LEVELS IN THE RAT TESTIS AFTER ETHANE-DIMETHANE SULFONATE-INDUCED DEGENERATION OF LEYDIG-CELLS

Short- (3-24 h) and long-term (4-50 days) changes in sulphated glycopr otein-2 (SGP3) and ornithine decarboxylase (ODC) mRNA levels in the ad ult rat testis were studied following a single dose of ethane-dimethan e sulphonate (EDS), to destroy the Leydig cells. Distribution patterns of SGP-2 and ODC labelling were consistent with prevailing expression of the two transcripts in Sertoli cells and germ cells, respectively This pattern did not show appreciable changes following EDS administra tion. No labelling of SGP-2 mRNA was noted in the interstitium of cont rol and EDS-treated rats. This finding indicates that Leydig cell deat h induced by EDS is not associated with increased SGP-2 mRNA levels, a phenomenon related to apoptotic cell death in many tissues. Semi-quan titative densitometric analysis of the preparations demonstrated diffe rential changes in SGP-2 and ODC mRNA levels in:the tubular compartmen t following EDS treatment. At 6, but not at 3 and 12, h following EDS administration, SGP-2 mRNA levels showed a significant increase, possi bly secondary to a direct effect of the alkylating agent on Sertoli ce lls. A significant decrease in ODC mRNA levels was observed from day 7 to day 28, matching degenerative changes in the seminiferous epitheli um. In contrast, a decrease in SGP-2 transcript levels was observed fr om days 21-35 after treatment. In conclusion, our findings demonstrate that SGP3 mRNA, a putative marker of apoptosis, is not altered in the testicular interstitium during EDS-induced degeneration of Leydig cel ls. In the tubular compartment, the content of both ODC and SGP-2 mRNA s following EDS administration appears to be dependent mostly on the i ntegrity of the germ cell complement and not to be influenced directly by changes in testosterone levels.