Application of fecal steroid techniques to the reproductive endocrinology of female verreaux's Sifaka ( Propithecus verreauxi )

Solid phase extraction, high performance liquid chromatography, and radioimmunoassay were used to test the validity of fecal steroid analysis for assessing ovarian function in sifaka ( Propithecus verreauxi ). Daily fecal samples were collected over a 4 month period from two cycling female sifaka, and single samples were collected from females during normal gestation and males while housed at the Duke University Primate Center. Tests of radioimmunoassay validity indicated that solid phase extraction and microradioimmunoassay techniques were reliable and accurate methods for quantifying ovarian steroids in sifaka feces. The progesterone (P 4 ) antibody specifically quantitated only P 4 , while several estrogen metabolites made small contributions to immunoreactive measures of estradiol (E 2 ). A 1:10 dilution reduced these contributions to 3–15% of the estimated E 2 concentration. Although the spectral data suggested that E 2 was not the major metabolite present, it accounted for the majority of the immunoreactivity at normal assay dilutions. Fecal profiles of immunoreactive E 2 and P 4 in the conceptive female resembled serum profiles of other strepsirhines. E 2 and P 4 were elevated at the end of the conceptive cycle and were more markedly increased in late pregnancy in the two pregnant females. Mating behavior and indices of sexual interest were observed in conjunction with E 2 peaks, although not all peaks were accompanied by observations of sexual behavior. © 1995 Wiley‐Liss, Inc.