| Abstract: | The effects of estradiol benzoate (EB), ethinyl estradiol (EE), and mestranol in different dosages on serum luteinizing hormone (LH) and follicle stimulating hormone (FSH) levels were measured by dioxane-radioimmunoassay at intervals of hours and days. All postmenopausal women studied here reacted with a pronounced suppression of both FSH and LH. The LH decline starts 4-10 hours earlier than FSH and returns - after the minumum on Days 2-3 - to the controls on Days 5-6, while the FSH levels show a longer suppression. Neither in the type of estrogen nor in the administered dose a marked qualitative difference could be observed. Only after 3 mg EE and 15 mg mestranol a prolonged inhibitory effect on FSH and LH became evident. Results in premenopausal women were quite different. In 7 women with a history of amenorrhea or anovulatory cycles 5 mg EB was given. A small decline after 24 hours was followed by a sharp rise of LH 1 day later which is comparable to the preovulatory LH peak. In the subsequent days values returned to control levels. The FSH curve did not show a similar peak. Only 1 woman ovulated and became pregnant. In another group of 11 women with normal menstrual cycles, 5 mg EB was injected at different times of the follicular, periovulatory, and luteal phases. The patterns of serum LH and FSH were comparable to the results in amenorrheic patients. In all cases an LH peak appeared on Days 2-3, which seemed to be higher in the preovulatory than in the postovulatory phase. The FSH curves remained uncharacteristic with small oscillations. The role of the physiological follicular estrogen peak for triggering the LH surge is discussed as well as the possibility of checking the response of the hypothalamic-hypophyseal system by exogenous estrogen application. |
