Failure of Daily Injections of Ketamine HCI to Adversely Alter Menstrual Cycle Length,Blood Estrogen,and Progesterone Levels in the Rhesus Monkey 1

Abstract

Summary

This study was carried out using 30 adult female rhesus monkeys in order to determine the effects of daily administration of ketamine HC1 (8-10 mg/kg) upon menstrual cycle length, incidence of ovula-tory menstrual cycles, and blood estrogen and progesterone levels throughout the cycle. In physically restrained control monkeys (25 cycles subjected to daily blood sampling) there were 14 of 25 or 56% ovu-latory cycles, and in ketamine-treated monkeys (32 menstrual cycles subjected to daily blood sampling) there were 28 of 32 or 88% ovulatory cycles. The length of the menstrual cycle was the same in both groups. The levels and time course of peripheral serum estrogen and progesterone levels were the same in the ovulatory cycles of both groups. In some of the control cycles (30%) and in some of the ketamine-treated cycles (25%) there were luteal phases in which the preovulatory estrogen levels were normal and in which the luteal-phase progesterone levels were low and variable 6-8 days after the preovulatory surge. It can be concluded that the daily use of ketamine HC1 does not significantly alter menstrual cycle length, or serum estrogen or progesterone levels throughout the menstrual cycle. It reduced the incidence of anovulatory cycles and premature menstrual induction probably by reducing the stress of restraining the monkey for the purpose of taking a blood sample.

This research was supported by Research Grants HD-03315 and HD-08834 from the National Institute of Child Health and Human Development, USPHS, and by a contract from the World Health Organization.