Androgens and innate immunity in rehabilitated semi‐captive orangutans (Pongo pygmaeus morio) from Malaysian Borneo

Abstract

Despite the implications for the development of life-history traits, endocrine-immune trade-offs in apes are not well studied. This is due, in part, to difficulty in sampling wild primates, and lack of methods available for immune measures using samples collected noninvasively. Evidence for androgen-mediated immune trade-offs in orangutans is virtually absent, and very little is known regarding their pattern of adrenal development and production of adrenal androgens. To remedy both of these deficiencies, sera were collected from orangutans (Pongo pygmaeus morio) (N = 38) at the Sepilok Orangutan Rehabilitation Centre, Sabah, Malaysia, during routine health screenings. Testosterone, dehydroepiandrosterone (DHEA), and dehydroepiandrosterone-sulfate (DHEA-S) were assayed, along with two measures of functional innate immunity. DHEA-S concentrations, but not DHEA, increased with age in this sample of 1-18 year old animals. DHEA concentrations were higher in animals with higher levels of serum bacteria killing ability, while DHEA-S and testosterone concentrations were higher in animals with reduced complement protein activity. Patterns of DHEA-S concentration in this sample are consistent with patterns of adrenarche observed in other apes. Results from this study suggest that in addition to testosterone, DHEA and DHEA-S may have potent effects on immunological activity in this species.

The role of dehydroepiandrosterone on functional innate immune responses to acute stress

“…Additionally, DHEA‐S concentrations are inversely related to severity of malaria and Schistosoma infections in humans (Kurtis et al, ; Leenstra et al, ). A positive association is also found between markers of innate immunity and DHEA in wild orangutans, with similar results in humans (Prall & Muehlenbein, ; Prall et al, ).…”

“…DHEA‐S is not known to have direct effects on immunity, but is thought to mediate its activity via conversion of other androgens and estrogens. Previous research indicates that elevated DHEA‐S is related to a decrease of some immune parameters (Prall & Muehlenbein, ; Prall et al, ) and increase in others (Hodges‐Simeon, et al, in review). Elevated DHEA‐S may signal either increased enzymatic expression of hydroxysteroid sulfotransferase, which converts DHEA to DHEA‐S, or reduced expression of steroid sulfatase, reflecting a reduction in available DHEA.…”

Nutritional Phases in Prader-Willi Syndrome: Evolutionary and Clinical Interpretations

“…Adrenarche occurs at around the age of weaning in great apes: bonobos wean after four years [22] with increases in adrenal androgens after five years [23]; orangutans wean after seven years [24] with increases in adrenal androgens after eight years [25]. Campbell noted that increased production of adrenal androgens accompanies independence from mothers at weaning in rodents and monkeys but occurs much later than weaning in humans [26].…”

The tempo of human childhood: a maternal foot on the accelerator, a paternal foot on the brake

“…16,17 Hormonal changes also occur as primates undergo these nutritional shifts. Adrenal androgens increase at about 5 years of age in semi-captive bonobos, chimpanzees, and gorillas 18,19 and at about 8 years of age in orangutans, 20 roughly corresponding with ages at weaning: 7-8 years in orangutans and 3-5 years in the other great apes (Table 1). This correlation, based on limited data, suggests that adrenal androgens may play a role in the increased independence observed in juvenile apes at weaning.…”