Rafaela SC Takeshita

Changes in steroid concentrations have profound effects on development and aging. In particular, adrenal hormones are associated with longevity and brain maturation, making them crucial for understanding human evolution. Previous studies in primates reported interspecies difference in circulating concentrations of dehydroepiandrosterone (DHEA) and dehydroepiandrosterone-sulfate (DHEAS) and in the timing of adrenarche (postnatal increase in the release of these hormones). High concentrations of DHEA/S are unique to primates and have been hypothesized to enhance brain complexity and promote longevity, being pivotal for human origins. This project will examine age-changes in DHEAS levels in nine primate genera. For this purpose, we have initiated a collaborative effort with 19 national and 8 international institutions to establish a sample population of non-human primates consisting of 220 individuals. Comparative analyses to link DHEA/S secretion with life history, brain size and diet among closely related species will reveal to what extent ecological factors played a role in neurochemical changes associated with K-selected traits. This non-invasive study allows field anthropologists to take this indirect approach to neuroendocrine mechanisms without animal manipulation and it will have a major impact in our understanding of the origins and the role of DHEA/S in brain evolution and longevity.