ACTH

Adrenocorticotrophic hormone (ACTH) is a polypeptide hormone that is synthesized and secreted by the anterior pituitary gland. ACTH forms part the hypothalamic-pituitary-adrenal axis (HPA axis), and its production is stimulated by corticotropin-releasing hormone (CRH) from the hypothalamus. ACTH acts on the adrenal cortex, by increasing the conversion of cholesterol to pregnenolone, to stimulate the release of mineralocorticoids, androgenic steroids, and glucocorticoids, namely, cortisol (Martin et al. 1977).

Along with CRH, ACTH is produced in the response to stress, stimulating an increase in production and secretion of cortisol. The secretion of ACTH is subject to negative feedback, where increased cortisol levels reduce the secretion of ACTH. It also controls its own secretion through short loop feedback via CRH. ACTH is not only secreted in response to stress but also a pulsatile manner, which is under neural control (Martin et al. 1977). The circadian secretion of ACTH increases...