Figure 1: The effect of stress on the hypothalamic-pituitary-adrenal axis. The hypothalamus secretes both CRH and AVP from the paraventricular nucleus which stimulate the production of ACTH in the anterior pituitary. ACTH travels via the blood until it stimulates the adrenal gland to secrete cortisol. Cortisol acts via a negative feedback mechanism mediated by MR and GR in the hypothalamus and GR in the anterior pituitary, which ultimately causes a decrease in secretion of CRH, AVP, and ACTH. CRH: corticotropin releasing hormone; AVP: arginine vasopressin; ACTH: adrenocorticotropic hormone; MR: mineralocorticoid receptor; GR: glucocorticoid receptor.