Adrenocorticotropic hormone (ACTH)

Definition

Adrenocorticotropic hormone (ACTH) is a peptide hormone produced by the anterior pituitary gland. It stimulates the adrenal cortex to release cortisol and other glucocorticoids, which are crucial for stress response and metabolism regulation.

5 Must Know Facts For Your Next Test

1. ACTH is released in response to corticotropin-releasing hormone (CRH) from the hypothalamus.
2. It follows a diurnal rhythm, with peak levels in the early morning and lowest levels at night.
3. ACTH secretion is part of the hypothalamic-pituitary-adrenal (HPA) axis, which plays a key role in stress response.
4. Elevated ACTH levels can indicate conditions like Addison's disease or Cushing's disease.
5. Synthetic ACTH is sometimes used in diagnostic tests to assess adrenal gland function.

Review Questions

• What triggers the release of ACTH from the anterior pituitary gland?
• How does ACTH affect the adrenal cortex?
• What are some clinical conditions associated with abnormal ACTH levels?

Related terms

Corticotropin-releasing hormone (CRH): A hormone released by the hypothalamus that stimulates the secretion of ACTH by the anterior pituitary.

Cortisol: A glucocorticoid hormone produced by the adrenal cortex that helps regulate metabolism and stress responses.

Hypothalamic-pituitary-adrenal (HPA) axis: A complex set of interactions among the hypothalamus, pituitary gland, and adrenal glands that regulate stress responses, digestion, immune system, mood and emotions.