The acute effect of oestrogens on testosterone production appears not to be mediated by testicular oestrogen receptors.
Scatchard binding analysis was performed to measure the cytoplasmic oestrogen receptor in the testis of rats. After treatment of rats with the antioestrogen tamoxifen no oestrogen receptor binding was found in testicular low speed supernatant between 12 and 96 h after treatment. Such tamoxifen-treated rats were used to study the acute effect of oestrogens on testosterone secretion, both in vivo and in vitro. Injection of oestradiol benzoate (50 microgram, 24 h prior to experiment) resulted in a significant depression of basal and LH-stimulated plasma testosterone levels in control rats and this effect was unchanged in tamoxifen-pretreated rats. In vitro, oestradiol-17 beta also inhibited the LH-induced rise in testosterone secretion by isolated testicular interstitial cells. This inhibition was not affected if the rats had been pretreated with tamoxifen. These results indicate that the inhibitory effects of exogenous oestrogens on testicular testosterone production are probably not mediated by the oestrogen receptor.
D000818:Animals; D003593:Cytoplasm / Q000378:metabolism; D004967:Estrogens / Q000494:pharmacology*; D066298:In Vitro Techniques; D007986:Luteinizing Hormone / Q000494:pharmacology; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D011960:Receptors, Estrogen / Q000502:physiology*; D013629:Tamoxifen / Q000494:pharmacology; D013737:Testis / Q000378:metabolism*; D013739:Testosterone / Q000096:biosynthesis*
D004967:Estrogens; D011960:Receptors, Estrogen; D013629:Tamoxifen; D013739:Testosterone; D007986:Luteinizing Hormone