The 84th Annual Meeting of the American Association of Physical Anthropologists (2015)


Adrenal development and androgen-immune interactions in orangutans (Pongo pygmaeus morio)

SEAN P. PRALL and MICHAEL P. MUEHLENBEIN.

Department of Anthropology, Indiana University, Bloomington

March 28, 2015 4:00, Grand Ballroom E/F/G Add to calendar

Humans, chimpanzees, and bonobos exhibit a similar pattern of adrenal development, with adrenal androgens exhibiting a sharp increase in adolescence. Like testosterone, these adrenal androgens play an important role in modulating physiology, but specific associations between immune function and the adrenal androgens dehydroepiandrosterone (DHEA) and dehydroepiandrosterone-sulfate (DHEA-S) are poorly understood, particularly in nonhuman primates for which there are few methods of non-invasive assessment of immune activity. The existence of adrenarche in orangutans has not been assessed, and there are few studies examining variability in immune function in this species. To remedy these deficiencies, sera were collected from orangutans (Pongo pygmaeus morio) (N = 38) at the Sepilok Orangutan Rehabilitation Centre, Sabah, Malaysia, during routine health screenings. Two measures of functional innate immunity (using a bacteria killing assay and a hemolytic complement assay) were compared to the androgens testosterone, DHEA, and DHEA-S. DHEA-S concentrations demonstrated elevations in adolescent animals in a pattern very similar to other apes. Additionally, while DHEA concentrations were higher in animals with high levels of serum bacteria killing ability, DHEA-S and testosterone were elevated in animals with reduced complement protein activity. These results suggest a differential role for androgens in influencing innate immune activity, and in particular an important role for DHEA and DHEA-S in influencing immunity. These results also are the first to suggest the presence of adrenarche in orangutans.

This work was supported by Indiana University to MPM.