Validation of a dehydroepiandrosterone-sulfate assay in three platyrrhine primates (Alouatta caraya, Aotus azarae infulatus and Sapajus apella).

Abstract

The hormone dehydroepiandrosterone (DHEA) and its sulfate ester (DHEAS) are the most abundant circulating steroids in human and some nonhuman primates, and have been implicated in development, aging and in stress modulation. We aimed to validate a commercially available enzyme immunoassay kit to measure DHEAS in feces and serum of three platyrrhine primate species (Alouatta caraya, Aotus azarae infulatus, and Sapajus apella) in captivity. We collected serum samples from one male and one female from each species. To validate the kit for fecal samples, we conducted a physiological validation by administering DHEA orally to one adult female of each species. We also measured fecal DHEAS levels in four female Alouatta caraya individuals during the third semester of gestation and in two females following parturition. We obtained a total of 54 fecal samples and 6 serum samples from 10 individuals. We validated the assay analytically by testing parallelism and accuracy tests in both fecal and serum extracts for all species. We observed a peak in DHEAS 24 h following oral DHEA administration in all three species, with A. caraya presenting the strongest response and highest baseline concentrations. DHEAS levels were elevated in pregnant A. caraya (57,843.86 ± 37,160.31 ng/g) and declined after parturition (1,539.07 ± 2,894.74 ng/g). Our results demonstrated that these platyrrhines secrete measurable concentrations of DHEAS, with A. caraya secreting levels comparable to those of catarrhines. The EIA kit is valid for quantification of fecal and serum DHEAS, and it is useful for studies on stress and primate evolution.