Adrenocorticotropic hormone (ACTH)

Definition

Adrenocorticotropic hormone (ACTH) is a peptide hormone produced by the anterior pituitary gland that stimulates the adrenal cortex to release cortisol. It plays a crucial role in stress response and maintaining homeostasis.

5 Must Know Facts For Your Next Test

1. ACTH is synthesized from the precursor molecule proopiomelanocortin (POMC).
2. It acts on the adrenal cortex, particularly the zona fasciculata, to stimulate cortisol production.
3. ACTH secretion is regulated by corticotropin-releasing hormone (CRH) from the hypothalamus.
4. High levels of cortisol exert negative feedback on both CRH and ACTH production.
5. Disorders such as Addison's disease and Cushing's syndrome are associated with abnormal ACTH levels.

Review Questions

• What role does ACTH play in regulating cortisol levels?
• How does negative feedback regulate ACTH secretion?
• Which part of the adrenal cortex does ACTH primarily target?

Related terms

Corticotropin-Releasing Hormone (CRH): A hypothalamic hormone that stimulates the release of ACTH from the anterior pituitary.

Cortisol:

A glucocorticoid hormone released by the adrenal cortex that helps regulate metabolism, immune response, and stress.

Addison's Disease:

A disorder characterized by insufficient production of steroid hormones by the adrenal glands, often due to low levels of ACTH.