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

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.