Effects of Estrogens on Testicular Testosterone Production in vitro

Abstract

It has been suggested that treatment with estradiol (E2) in vivo decreases testosterone (T) production by a direct inhibitory effect on testicular steroidogenesis. To examine this possibility, decapsulated mouse and rat testes were incubated in Krebs-Ringer bicarbonate buffer containing glucose, hCG and various concentrations of E2 or diethylstilbestrol (DES). At the concentration of 50 µg/ml, both E2 and DES significantly reduced the accumulation of T in the incubation medium. Lower doses of free estrogens were ineffective in this system, except for an inhibitory action of 5 µg DES/ml in the incubations of mouse testes. The possibility that esters of E2 can also influence testicular steroidogenesis directly, was examined by incubating mouse testes with various concentrations of E2 3-mono-benzoate (E2 B). Addition of 5 or 50 µg E2 B per ml produced a pronounced inhibition of T accumulation in this system, while 0.5 µg E2 B per ml had a slight but statistically significant inhibitory effect. When decapsulated mouse testes were incubated with 50µ g/ml of DES or E2 B in the absence of hCG, T accumulation was inhibited only by DES.