Adrenocorticotropic hormone

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Adrenocorticotropic hormone (ACTH or corticotropin) is a peptide hormone produced and secreted by the pituitary gland. It is an important player in the hypothalamic-pituitary-adrenal axis.

[edit] Production

ACTH synthesised from pro-opiomelanocortin (POMC) and secreted from corticotropes in the anterior lobe of the pituitary gland in response to the hormone corticotropin-releasing hormone (CRH) released by the hypothalamus.

[edit] Structure

ACTH consists of 39 amino acids, the first 13 of which (counting from the N-terminus) may be cleaved to form α-melanocyte-stimulating hormone (α-MSH). (This common structure is one reason that patients with hypercortisolism, in which ACTH levels are elevated, often present with excessively tanned skin.)

Together with ACTH, the hormones lipotropin, melanocyte-stimulating hormone (MSH), β-endorphin and met-enkephalin are also released.

[edit] Function

ACTH acts through the stimulation of cell surface ACTH receptors, which are primarily located on the adrenocortical cells. ACTH stimulates the cortex of the adrenal gland and boosts the synthesis of corticosteroids, mainly glucocorticoids but also mineralcorticoids and sex steroids (androgens).

ACTH is also related to the circadian rhythm in many organisms.

The half-life of ACTH in human blood is about 10 minutes.

[edit] Synthetic ACTH

ACTH is available as a synthetic derivative in the form of cosyntropin (synthetic ACTH), tradename Cortrosyn®.

[edit] Associated conditions

• Addison's disease
• Small cell carcinoma
• adrenoleukodystrophy
• Congenital adrenal hyperplasia
• Cushing's syndrome
• Nelson's syndrome

[edit] See also

• Pituitary-adrenal axis