Serum estradiol 17 beta, progesterone, and relative luteinizing hormone levels in Saimiri sciureus: cyclic variations and the effect of laparoscopy and follicular aspiration.

With increasing use of the squirrel monkey (Saimiri sciureus) in reproductive studies, a precise knowledge of the hormonal variations within the cycle becomes essential for timing of ovulation. The frequent utilization of laparoscopy for follicle aspiration and oocyte recovery warrants analysis of hormonal alterations. In the first study, estradiol 17 beta, progesterone, and luteinizing hormone (LH) levels were quantitated daily in the same group of 14 animals for 16 days. Serum estradiol and LH levels showed significant increases on day 4 of the cycle. Progesterone levels peaked on day 6. Based upon the hormonal peak intervals, the reproductive cycle of the squirrel monkey was estimated to be 8-9 days in length. Laparoscopy did not alter normal serum levels of estradiol, progesterone, and LH. Aspiration of the follicular contents, however, resulted in a significant decrease in estradiol and LH, and a rise in progesterone within 2 h.