Cyclic changes in the circulating and urinary levels of ovarian steroids in the adult female owl monkey (Aotus trivirgatus)

Abstract

Circulating levels of estrone and progesterone were measured by radioimmunoassays in plasma samples from 5 female owl monkeys on 60 consecutive days. Both steroids exhibited cyclic fluctuations and, based on nadir to nadir intervals, the ovarian cycle was estimated to be 15.92 .+-. 0.26 days. Levels of estrone and pregnanediol-3.alpha.-glucuronide were also measured in daily urine samples. The fluctuations of urinary steroids reflected those observed in plasma. Ketamine sedation had no effect on the length of the cycle. Peak values of plasma progesterone and estrone were 250.48 .+-. 11.37 and 3.59 .+-. 0.066 ng/ml, respectively. There was no clear hormonal distinction between the follicular and luteal phase of the cycle in these owl monkeys.