Adrenocorticotrophic hormone

Adrenocorticotrophic hormone (ACTH), also known as corticotropin, is a polypeptide tropic hormone produced and secreted by the anterior pituitary gland. It is an important player in the body's stress response and has a crucial role in maintaining homeostasis.

Function

ACTH stimulates the adrenal cortex, the outer part of the adrenal gland, to produce and release cortisol. Cortisol is a steroid hormone that plays a role in the stress response, maintaining blood pressure and cardiovascular function, slowing the immune response, and balancing the effects of insulin in breaking down sugar for energy.

Production and Secretion

The production and secretion of ACTH is regulated by the hypothalamus, a small region of the brain. The hypothalamus releases corticotropin-releasing hormone (CRH), which travels to the anterior pituitary gland, stimulating the release of ACTH. This process is an example of a negative feedback loop, as high levels of cortisol in the body signal the hypothalamus to stop producing CRH and therefore reduce ACTH production.

Clinical Significance

Abnormal levels of ACTH can lead to a variety of health problems. Overproduction of ACTH can lead to Cushing's syndrome, a condition characterized by a round face, high blood pressure, high blood sugar levels, and obesity. On the other hand, underproduction of ACTH can lead to Addison's disease, which can cause fatigue, low blood pressure, weight loss, and darkening of the skin.

Measurement

The ACTH test is a blood test that measures the level of ACTH in the blood. This test can help diagnose conditions related to the adrenal gland, such as Addison's disease and Cushing's syndrome.

See Also

• Cortisol
• Pituitary gland
• Adrenal gland
• Cushing's syndrome
• Addison's disease