ACTH
Meaning of ACTH: ACTH is a pituitary hormone that signals the adrenal glands to release cortisol, rising during stress and following a natural daily rhythm.
Definition of ACTH
ACTH, or adrenocorticotropic hormone, is a hormone produced by the anterior pituitary gland, a small gland located at the base of the brain. It travels through the bloodstream to act on the outer layer of the adrenal glands, known as the adrenal cortex, where it stimulates the production and release of cortisol and related corticosteroid hormones.
ACTH release is controlled by the hypothalamus, a nearby brain structure that signals the pituitary through its own hormone, and the amount of ACTH released normally follows a daily rhythm, rising before waking and declining over the course of the day, while also increasing in response to physical or emotional stress.
Because ACTH sits between the brain and the adrenal glands in this signaling pathway, measuring ACTH alongside cortisol helps determine whether an abnormal cortisol level originates from a problem in the pituitary gland, the adrenal glands themselves, or elsewhere in the body.
Also known as
Used in a sentence
ACTH levels were measured alongside cortisol to help determine the cause of the patient's adrenal abnormality.
Good to know
Measuring ACTH together with cortisol helps determine whether abnormal cortisol levels originate from the pituitary gland, the adrenal glands, or another source, since each pattern produces a different relationship between the two hormones.