Regulation of androgen production by frog (Rana esculenta) testis: an in vitro study on the effects exerted by estradiol, 5 alpha-dihydrotestosterone, testosterone, melatonin, and serotonin.

The possible role of estradiol-17 beta (E2), testosterone (T), 5 alpha-dihydrotestosterone (DHT), melatonin, and serotonin on the regulation of androgen (A) production by the frog, Rana esculenta, testes was studied in vitro. E2 (10(-6) M) inhibited A production whether alone or in combination with oLH (20 micrograms) after 6 hr incubation. After 24 hr incubation. A production was reduced by E2 concentration of around 10(-6) and 10(-9) M. Melatonin and serotonin did not induce any change whichever experimental condition was used. Preincubation for 6 hr with 10(-6) M T or DHT enhanced the oLH-stimulated A production after 18 hr incubation. These data suggest that steroids may regulate their intratesticular levels without passing into the blood stream.