ACTH

Adrenocorticotropic hormone

Adrenocorticotropic hormone (ACTH) is a hormone produced by the anterior pituitary gland that plays a crucial role in regulating the body’s response to stress. Its primary function is to stimulate the adrenal cortex to release cortisol, a key hormone involved in managing metabolism, immune response, and the body’s circadian rhythms.

In Addison’s disease, ACTH levels are often elevated due to low cortisol production, leading to skin hyperpigmentation. This happens because ACTH shares a precursor molecule (proopiomelanocortin) with melanocyte-stimulating hormone (MSH), which affects skin pigmentation. In Cushing’s syndrome, ACTH can be overproduced, leading to excess cortisol, resulting in distinctive features like “moon face” and central obesity.

ACTH testing is commonly used to diagnose adrenal insufficiency and helps clinicians assess pituitary function.