Differences in ovarian stimulation in human menopausal gonadotropin treated woman may be related to follicle-stimulating hormone accumulation.

Two groups of normal ovulatory women who displayed either a marked (high responders; HR) or a more subtle (low responders; LR) ovarian response to a fixed dose of human menopausal gonadotropins (hMG) were evaluated for differences in blood levels of hormones. Serum follicle-stimulating hormone (FSH) levels doubled during the first 3 days of treatment (to approximately 20 mIU/ml) in all patients; thereafter, the levels plateaued in LR but continued to rise steadily (to 35 mIU/ml) in HR. In the latter group, rise in estradiol (E2) and FSH was accompanied by an increase of luteinizing hormone (LH; two to five times) progesterone (P; four to eight times) testosterone (T; three to four times) and prolactin (PRL; 2 times) toward the end of the follicular phase. Positive correlation was found between FSH and E2 in HR and LR. Positive correlation was found, however, between LH, T, and P and between E2, P, and PRL only in HR. The extent of FSH accumulation in the circulation may be a principal factor in determining an individual's response to hMG therapy. Temporal changes of blood hormones indicated that the continuous rise in FSH levels in HR was associated with early luteinization of the follicles. Increased secretion of P in the follicular phase of these women (HR) probably synergized with the elevated E2 levels to elicit LH release. Similar changes in blood hormones were not found in LR.