Biology of Reproduction, Vol 23, 522-525, Copyright © 1980 by Society for the Study of Reproduction

Endocrine Characteristics of the Menstrual Cycle in the Assamese Monkey (Macaca assamensis)

¹ Center for Reproductive Sciences, Department of Obstetrics and Gynecology and Department of Physiology, Columbia University, College of Physicians & Surgeons, New York, New York 10032

The endocrine characteristics of the menstrual cycle were determined in 16 Assamese monkeys (Macaca assamensis). Average cycle length was 32 ± 2 (± SEM) days which was divided into a 16 ± 1 day follicular phase and a 16 ± 1 day luteal phase. LH and FSH concentrations were fairly constant throughout the cycle except at midcycle when both gonadotropins surged. At this time LH concentrations increased from 4 ± 2 to 17 ± 4 µg/ml (mean ± SEM) and FSH from 3 ± 1 to 9 ± 1 µg/ml. Estrogens also increased at midcydle from 275 ± 75 to 432 ± 89 pg/ml. Progesterone rose from less than 0.5 ng/ml during the follicular phase to between 2 and 4 ng/ml during the luteal phase. Although there was variation between animals, the concentrations and patterns of these hormones were similar to those reported for other species of macaques. These results suggest that the Assamese monkey can serve as an appropriate model for the study of primate reproductive physiology.

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ACKNOWLEDGMENTS The research reported in this paper was supported by NIH grant HD-05077. We would like to thank the Contraceptive Development Branch and the National Pituitary Agency of the NIH for the precious gift of reagents for the gonadotropin radioimmunoassays. We thank A. Peterson, D. McNicol, M. Gottardis, and B. Sears for their excellent technical help, and J. Wehrenberg and K. Hildreth for their secretarial assistance.