UC Davis

Steroid hormones are critical to the regulation of sociosexual behavior. Their role in the formation of pair bonds is complicated by the relative scarcity of this social system in mammals, as well as species and taxonomic differences in endocrine systems. In the present study, we experimentally manipulated the hypothalamic-pituitary-adrenal axis in female titi monkeys (Plecturocebus cupreus), a neotropical monkey studied for its strong, selective pair bonds. We validated an assay for plasma and urinary cortisol in this species, showing a strong suppression of cortisol following dexamethasone injection, and a significant but somewhat blunted response to adrenocorticotrophin hormone (ACTH) stimulation. Urinary androgens did not change in response to dexamethasone or ACTH. Plasma and urinary cortisol were moderately correlated, whereas urinary cortisol and androgens were only correlated when extreme cortisol values were included. In this study, we laid groundwork for studying the role of glucocorticoids and androgens (and eventually, their interactions with peptides) in the behavioral endocrinology of pair bonds in female titi monkeys.