Serum antimüllerian hormone predicts ovarian reserve in a monkey model

A monkey model of the menopausal transition (perimenopause) would facilitate efforts to understand better the effect of hormonal fluctuations during this life phase on the initiation of chronic diseases associated with the postmenopausal years. Antimüllerian hormone (AMH) is a promising marker of ovarian reserve (primordial follicle number) in women. Here, we describe the relationship between AMH and ovarian reserve in cynomolgus monkeys (Macaca fascicularis) estimated to be 12 to 15 years of age (approximately 36-45 y in women).

The results of daily vaginal swabbing (to detect menses) and thrice weekly blood sampling for 12 weeks indicate that AMH is relatively stable across the menstrual cycle (intraclass correlation, approximately 0.80), with a slight although significant (P < 0.02) reduction (approximately 1.4-fold) on days 2 to 5 postovulation. Substantial interindividual variation in AMH concentrations were observed between monkeys, with values ranging from 4.46 +/- 0.17 to 18.80 +/- 0.71 ng/mL (mean +/- SE). Antimüllerian hormone concentrations were reduced by approximately 63% after the removal of one ovary (7.6 +/- 0.77 vs 2.75 +/- 0.37 ng/mL; P < 0.001; n = 19) and were below the level of detection after the removal of both ovaries (5.8 +/- 0.42 to <0.05 ng/mL; P < 0.001; n = 84), suggesting that the ovary is likely to be either the major or the sole source of AMH in the monkey. Finally, we examined the association between AMH and primordial, primary, and secondary follicles in 29 monkeys and found significant associations with all follicle types (r = 0.78, r = 0.66, and r = 0.80, respectively; P < 0.01).

The relationship between AMH and ovarian reserve in the monkey is similar to that in women, suggesting that monkeys may be a useful model for studying hormonal fluctuations across the menopausal transition.