On the effects of oestrogen in the male. Some effects of different oestrogenic substances in rats and men with prostatic carcinoma

Abstract

In vitro incubations of human testicular tissue responded to human chorionic gonadotrophin with testosterone release in a dose-dependent manner. The release of testosterone increased with incubation time. The stimulated release of testosterone was inhibited by oestradiol and ethinyl oestradiol in a dose-dependent manner, suggesting that these oestrogens exert direct inhibitory effects on the human Leydig cells. Estramustine phosphate, estromustine, diethylstilboestrol and diethylstilboestrol diphosphate did not inhibit testosterone release. Hypophysectomized rats were treated for 8-9 days with human chorionic gonadotrophin, which maintained testicular blood flow within the physiological range. Some of the animals received additional treatment with oestradiol or estromustine. Oestradiol and estromustine depressed plasma testosterone concentration. In contrast to estromustine, oestradiol inhibited testicular blood flow, as measured by the microsphere technique. Intact rats were castrated, supplemented with testosterone and concomitantly treated with different oestrogenic substances. Testosterone supplementation induced increase of prostatic blood flow, which was inhibited by oestradiol, ethinyl oestradiol or diethylstilboestrol. Estramustine and estromustine had no effect on prostatic blood flow. The growth of a transplantable rat prostatic carcinoma (Dunning R3327H) was studied after castration, testosterone substitution or testosterone substitution in combination with oestradiol treatment. Oestradiol inhibited tumour growth, possibly by direct action. The blood flow in tumours in intact animals decreased with increasing tumour volume. Oestradiol treatment enhanced tumour blood flow. The oestrogenic effects of estramustine phosphate, ethinyl oestradiol/polyoestradiol phosphate or orchiectomy were studied in previously untreated prostatic carcinoma patients by measuring serum levels of liver proteins (pregnancy zone protein and sex hormone binding globulin) and pituitary hormones (luteinizing hormone, follicle stimulating hormone and prolactin) during a 6 month period. Both medical treatments induced marked but quite comparable changes of the proteins. Apart from the increase of follicle stimulating and luteinizing hormones, no changes were observed in these serum proteins after orchiectomy.