Fecal Progestins and Estrogens for Endocrine Monitoring of Ovarian Cycle and Pregnancy in Sumatran Orangutan (Pongo abelii)

Abstract

The purpose of the present study was to determine patterns of fecal immunoreactive progestins (progesterone, iP_4 and pregnanediol-glucuronide, iPdG) and estrogens (estradiol-17β, iE_2 and estrone, iE_1), and to investigate the reproductive status and ovarian cycle of female Sumatran orangutans, Pongo abelii (n=2). In two females, menstruation lasted for 3.0±0.3 days (mean±SEM, n=17), and the menstrual cycle was 27.3±0.4 days (n=15 cycles). The ovarian cycle based on fecal iPdG profiles was 27.1±1.3 days (n=15 cycles), and based on fecal iE_2 profiles it was 26.8±2.4 days (n=17 cycles). Fecal iP_4 and iE_1 did not show cyclic changes during the non-pregnant stage. In the pregnant female, fecal levels of iP_4, iPdG, iE_2 and iE_1 during second half of pregnancy were significantly higher than those during non-pregnancy. These results suggest that fecal iPdG and iE_2 analyses are useful to demonstrate the ovarian cycle in Sumatran orangutans and their pregnancy could be diagnosed by any one of fecal iP_4, iPdG, iE_2 and iE_1 analyses.