Social suppression of cortisol in female marmoset monkeys: role of circulating ACTH levels and glucocorticoid negative feedback

• Published in: Psychoneuroendocrinology Vol. 29; no. 2; pp. 141 - 161
• Main Authors: Saltzman, W, Prudom, S.L, Schultz-Darken, N.J, Wittwer, D.J, Abbott, D.H
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01-02-2004; Elsevier
• Subjects: Adaptation, Physiological; Adrenal Cortex Function Tests; Adrenocorticotropic hormone; Adrenocorticotropic Hormone - blood; Adrenocorticotropic Hormone - drug effects; Animals; Behavioral psychophysiology; Biological and medical sciences; Callithrix; Cortisol; Dexamethasone; Dexamethasone - pharmacology; Dominance-Subordination; Feedback, Physiological; Female; Fundamental and applied biological sciences. Psychology; Glucocorticoids - physiology; Hormones and behavior; Hydrocortisone - blood; Hypothalamo-Hypophyseal System - drug effects; Hypothalamo-Hypophyseal System - metabolism; Marmoset; Negative feedback; Ovulation - blood; Pituitary-Adrenal System - drug effects; Pituitary-Adrenal System - metabolism; Psychology. Psychoanalysis. Psychiatry; Psychology. Psychophysiology; Social Environment; Stress, Psychological - blood; Subordination; Subordination; Marmoset; Negative feedback; Cortisol; Dexamethasone; Adrenocorticotropic hormone; Corticosteroid; Hypothalamohypophysoadrenal axis; Steroid hormone; Callithrix jacchus; Antiinflammatory agent; Feedback regulation; Hydrocortisone; Glucocorticoid; Vertebrata; Mammalia; Social behavior; Adenohypophyseal hormone; Social dominance; Social interaction; Animal; Adrenal hormone; Primates; Simioidea; Female
• ISSN: 0306-4530; 1873-3360
• DOI: 10.1016/S0306-4530(02)00159-2

Behaviorally subordinate female common marmoset monkeys (
Callithrix jacchus) exhibit pronounced, chronic reductions of circulating cortisol levels. Cortisol suppression in these animals is mediated in part by adrenocortical hyporesponsiveness to adrenocorticotropic hormone (ACTH). In addition, we hypothesized that social subordination may activate a central, neurally mediated mechanism to further inhibit hypothalamo-pituitary-adrenal function. In this study, therefore, we evaluated basal plasma cortisol and ACTH concentrations, as well as cortisol and ACTH responses to dexamethasone (DEX), in dominant and subordinate females to initially characterize such a mechanism. Morning plasma cortisol and ACTH levels were determined before, and 1, 2, and 3 days following administration of DEX (0.5, 1.0, or 5.0 mg/kg, IM) or saline. Baseline cortisol concentrations prior to DEX treatment were significantly lower in subordinate females than in dominants, as previously reported. However, ACTH concentrations in the same blood samples did not differ between the two groups. Furthermore, dominant and subordinate females showed similar cortisol and ACTH responses to DEX. These results indicate that reduced circulating cortisol levels in subordinate females are not associated with either altered circulating ACTH concentrations or enhanced responsiveness to glucocorticoid negative feedback. However, the finding that basal ACTH levels are not elevated in subordinate females as compared to dominants, in spite of low circulating cortisol concentrations, suggests that ACTH secretion in subordinate females is restrained by a steroid-independent inhibitory mechanism operating at the level of the brain or pituitary.