Adrenokortikotropen

Adrenokortikotropen, often abbreviated as ACTH, is a polypeptide hormone produced and secreted by the anterior pituitary gland. Its primary function is to regulate the production and release of steroid hormones, particularly glucocorticoids like cortisol, by the adrenal cortex. ACTH plays a crucial role in the body's stress response, initiating the "fight-or-flight" mechanism by stimulating the adrenal glands.

The secretion of ACTH is tightly controlled by the hypothalamus through corticotropin-releasing hormone (CRH). CRH is released from the hypothalamus and travels to the anterior pituitary, where it stimulates the production and release of ACTH. In turn, ACTH travels through the bloodstream to the adrenal cortex, binding to specific receptors on the cells of the adrenal glands. This binding triggers a cascade of intracellular events that lead to the synthesis and secretion of glucocorticoids.

Cortisol, the main glucocorticoid released in response to ACTH, has widespread effects on the body. It influences metabolism by promoting gluconeogenesis and lipolysis, helps suppress the immune system, and plays a role in regulating blood pressure and cardiovascular function. The levels of ACTH and cortisol are subject to a negative feedback loop. High levels of cortisol in the bloodstream inhibit the release of both CRH from the hypothalamus and ACTH from the pituitary gland, thus maintaining hormonal balance. Disruptions in the ACTH pathway can lead to various endocrine disorders, such as Cushing's disease and Addison's disease, characterized by either excessive or deficient cortisol production.