Pituitary LH and FSH secretion and responsiveness in women of old age.

The plasma concentrations and episodic fluctuations of immunoreactive FSH and LH as well as the pituitary sensitivity to LH-RH stimulation were evaluated in post-menopausal women. The subjects were divided into 4 groups according to age. Group 1: 60-70 years old (n = 11), group 2: 70-80 years old (n = 22), group 3: 80-90 years old (n = 31) and group 4: 90-100 years old (n = 8). Standards used in gonadotrophin radioimmuno-assays included the LER-907 preparation and a pooled post-menopausal serum. Since it was found that circulating gonadotrophins have an immunological pattern different from that shown by the pituitary preparation, the results were expressed in mIU/ml calculated accordingly to the immunological behavior of pooled post-menopausal sera. The mean (+/- SE) plasma levels of FSH (mIU/ml) were: group ): 105 +/- 9.5, group 2: 149.3 +/- 10.5, group 3: 124.8 +/- 7.1 and group 4: 149.4 +/- 25.3. The mean (+/- SE) plasma levels of LH (mIU/ml) were: group 1: 81.9 +/- 12.5, group 2: 95.4 +/- 9.9, group 3: 84.3 +/- 7.7 and group 4: 113.5 +/- 19.1. No statistically significant differences were observed among the 4 groups. One patient from each group was randomly selected in order to evaluate their LH and FSH episodic release as well as their pituitary responsiveness to exogenous stimulation. A pulsatile plasma pattern of gonadotrophin and a normal pituitary response to LH-RH injection were observed in the 4 patients studied. The results are interpreted as demonstrating that normal pituitary gonadotrophin function and pituitary reserve and responsiveness to exogenous stimulation are maintained in women of advanced age.