What is the key function of ACTH?

The key function of adrenocorticotropic hormone (ACTH) is to stimulate the production and release of cortisol from the adrenal cortex. ACTH is secreted by the anterior pituitary gland in response to corticotropin-releasing hormone (CRH) from the hypothalamus during times of stress or low blood cortisol levels. Upon release, ACTH acts on the adrenal cortex, specifically the zona fasciculata, promoting the synthesis and secretion of glucocorticoids, primarily cortisol.

Cortisol plays a critical role in the body's response to stress, managing metabolism, reducing inflammation, and regulating blood sugar levels, among other functions. By stimulating cortisol production, ACTH helps to ensure that the body can effectively respond to stressors.

Understanding this function is crucial because it highlights how the hypothalamic-pituitary-adrenal (HPA) axis operates and how hormonal regulation affects various physiological responses during stress.