Net Increase in Stimulatory Input Resulting from a Decrease in Inhibin B and an Increase in Activin A May Contribute in Part to the Rise in Follicular Phase Follicle-Stimulating Hormone of Aging Cycling Women1

• Published in: The journal of clinical endocrinology and metabolism 1998-09, Vol.83 (9), p.3302-3307
• Main Authors: Reame, Nancy E, Wyman, Tammy L, Phillips, David J, de Kretser, David M, Padmanabhan, Vasantha
• Format: Article
• Language: English
• ISSN: 0021-972X; 1945-7197
• DOI: 10.1210/jcem.83.9.5130

Recent studies suggest that an age-related decline in ovarian inhibin B may play a role in the increase in follicular phase FSH in menstrual cycles of older women. Considering that the peripheral feedback regulation of FSH is dictated by the overall tone of inhibins, activins, and follistatins as well as estradiol, it is essential to determine the relative inputs of all of these regulators in assessing whether the collective peripheral input to FSH is one of inhibition or stimulation. To test the hypothesis that changes in the overall tone of peripheral feedback may contribute to this hallmark sign of aging, we compared the concentrations of dimeric inhibin A, inhibin B, activin A, and total and free follistatin in 7 young (mean age, 27.9 ± 2.6 yr) and 10 older (mean age, 43.6 ± 0.9 yr) cycling women during the follicular (FOLL; cycle day 6) and midluteal (ML; 7 days post-LH surge) phases of the menstrual cycle. Subjects were preselected on the basis of FOLL phase FSH levels (older, ≥8.0 mIU/mL; younger,