Dose-dependent induction of ornithine decarboxylase and S-adenosyl-methionine decarboxylase activity by testosterone in the accessory sex organs of male rats.

Abstract

The dose-dependent induction of ornithine decarboxylase (ODC) and adenosylmethionine decarboxylase (AMDC) activity in the different lobes of the prostate and the seminal vesicles (SV), 24 hours after administration of testosterone to castrated Wistar rats, has been studied. ODC and AMDC activities were low in all lobes 10 days after castration. A dose of approximately 300 micrograms testosterone/100 g body weight (B.W.) gave an ODC activity of 50 percent of maximum response, and at 600 micrograms/100 g B.W. maximum activity was reached in all the prostatic lobes and the SV. In the lateral and dorsal prostate, and the coagulating gland, the dose of testosterone giving 50% of maximum AMDC activity was reached after administration of between 450 and 600 micrograms/100 g B.W. In the ventral prostate and SV, the dose giving a 50% response was approximately 700 micrograms/100 g B.W. In conclusion, all prostatic lobes showed a clear dose-response relationship concerning the activity of ODC and AMDC following administration of different doses of testosterone. We have found minor differences in androgen responsiveness between the lobes when looking at the dose requirements for induction of AMDC activity. The dose-response curves could possibly be useful as a rapid in vivo bioassay for compounds with anti-androgenic properties in the prostate.