Adrenocorticotropic hormone

related topics
{disease, patient, cell}
{acid, form, water}

Adrenocorticotropic hormone (ACTH), also known as 'corticotropin', is a polypeptide tropic hormone produced and secreted by the anterior pituitary gland. It is an important component of the hypothalamic-pituitary-adrenal axis and is often produced in response to biological stress (along with corticotropin-releasing hormone from the hypothalamus). Its principal effects are increased production and release of corticosteroids and, as its name suggests, cortisol from the adrenal cortex.

Contents

Production and regulation

ACTH is synthesized from pre-pro-opiomelanocortin (pre-POMC). The removal of the signal peptide during translation produces the 267-amino acid polypeptide POMC, which undergoes a series of post-translational modifications such as phosphorylation and glycosylation before it is proteolytically cleaved by endopeptidases to yield various polypeptide fragments with varying physiological activity. These fragments include ACTH, β-lipotropin, γ-lipotropin, Melanocyte-Stimulating Hormone (MSH) and β-endorphin. POMC, ACTH and β-lipotropin are secreted from corticotropes in the anterior lobe (or adenohypophysis) of the pituitary gland in response to the hormone corticotropin-releasing hormone (CRH) released by the hypothalamus.[1]

In order to regulate the secretion of ACTH, many substances secreted within this axis exhibit slow/intermediate and fast feedback-loop activity. Glucocorticoids secreted from the adrenal cortex work to inhibit CRH secretion by the hypothalamus, which in turn decreases anterior pituitary secretion of ACTH. Glucocorticoids may also inhibit the rates of POMC gene transcription and peptide synthesis. The latter is an example of a slow feedback loop, which works on the order of hours to days, whereas the former works on the order of minutes.

Full article ▸

related documents
Hemoglobinopathy
Trimethoprim
Nicotinamide
Angiopathy
Ampicillin
Blood vessel
Proteinuria
Adrenal gland
Meconium
Perineum
Apraxia
Beta-lactamase
Non-Hodgkin lymphoma
General anaesthetic
Myalgia
Pathogen
Ileum
Grey matter
Pharynx
Ligament
Clinical chemistry
Fragile X syndrome
Cowpox
Hirsutism
Urology
Epidemic
Hepatology
Allergen
Paul Ehrlich
Hematology