Cortisol Production & the Hypothalamic–Pituitary–Adrenal Axis in PCOS
The glucocorticoid hormones – cortisol (in humans) and/or corticosterone (in animals) – are secreted in the adrenal glands under the control hypothalamic structures and the pituitary gland, which form the structural organization of the hypothalamic–pituitary–adrenal (HPA) axis. In the hypothalamic areas, the cascade is in turn chiefly regulated by the corticotropin-releasing hormone (CRH) and arginine-vasopressin, whose release activates pro-opiomelanocortin in anterior pituitary corticotroph cells and the release of ACTH into peripheral blood, from where it targets receptors in the adrenal cortex to release glucocorticoid hormones. In the hypothalamus, the parvocellular cells of the paraventricular nucleus of the hypothalamus are the major information junction for the neuroendocrine response to both internal and external excitatory stimuli. There is a hierarchical organization of the responsive neurocircuitries upon the paraventricular nucleus, which is capable of integrating information from multiple limbic sources with internally generated and peripherally sensed information, thereby tuning the relative activity of the adrenal cortex. These circuits are particularly involved in the response to physical and psychological stress, both acute and chronic. In most organisms the system efficiently modulates the HPA axis in accordance with needs; however, there is a considerable individual variation in the HPA response disposition and some influence of genetic factors and early-life experience. Importantly, the organization of the HPA axis is under the control of sex hormones, thereby explaining some physiological and pathophysiological differences between the sexes in its regulation and activity.[12,13]
Expert Rev Endocrinol Metab. 2012;7(5):555-566. © 2012 Expert Reviews Ltd.