Adrenocorticotropic hormone

Adrenocorticotropic hormone (ACTH; also adrenocorticotropin, corticotropin) is a

The half-life of ACTH in human blood is reported to be between ten and 30 minutes.^[5][6][7]

Structure

ACTH consists of 39

ACTH stimulates secretion of glucocorticoid steroid hormones from adrenal cortex cells, especially in the zona fasciculata of the adrenal glands. ACTH acts by binding to cell surface ACTH receptors, which are located primarily on adrenocortical cells of the adrenal cortex. The ACTH receptor is a seven-membrane-spanning G protein-coupled receptor.^[9] Upon ligand binding, the receptor undergoes conformation changes that stimulate the enzyme adenylyl cyclase, which leads to an increase in intracellular cAMP^[10] and subsequent activation of protein kinase A.

ACTH influences steroid hormone secretion by both rapid short-term mechanisms that take place within minutes and slower long-term actions. The rapid actions of ACTH include stimulation of cholesterol delivery to the mitochondria where the

The long term actions of ACTH include stimulation of the transcription of the genes coding for steroidogenic enzymes, especially P450scc, steroid 11β-hydroxylase, and their associated electron transfer proteins.^[10] This effect is observed over several hours.^[10]

In addition to steroidogenic enzymes, ACTH also enhances transcription of mitochondrial genes that encode for subunits of mitochondrial oxidative phosphorylation systems.^[11] These actions are probably necessary to supply the enhanced energy needs of adrenocortical cells stimulated by ACTH.^[11]

ACTH receptors outside the adrenal gland

As indicated above, ACTH is a cleavage product of the pro-hormone,

While working on her dissertation, Evelyn M. Anderson co-discovered ACTH with James Bertram Collip and David Landsborough Thomson and, in a paper published in 1933, explained its function in the body.^[16][17]

An active synthetic form of ACTH, consisting of the first 23 amino acids of native ACTH, was first made by Klaus Hofmann at the University of Pittsburgh.^[18]

Associated conditions

• Diseases of the pituitary, the gland that produces, among others, the hormone ACTH
• Hypopituitarism, the hyposecretion of ACTH in the pituitary, leading to secondary adrenal insufficiency (a form of hypocorticism)
• Addison's disease, the primary adrenal insufficiency (another form of hypocorticism)
• Cushing's syndrome, hypercorticism, one of the causes is hypersecretion of ACTH
• Small cell carcinoma
  , a common cause of ACTH secreted ectopically
• Congenital adrenal hyperplasia, diseases in the production of cortisol
• Nelson's syndrome, the rapid enlargement of the ACTH producing pituitary after the removal of both adrenal glands
• Adrenoleukodystrophy, can be accompanied by adrenal insufficiency
• West syndrome
  ("infantile spasms"), a disease where ACTH is used as a therapy
• epinephrine are produced.^{[citation needed}
  ]
• Critical illness-related corticosteroid insufficiency
• DAVID syndrome, a genetic disorder that is characterized by adrenocorticotropic hormone deficiency combined with common variable immunodeficiency and hypogammaglobulinemia.

See also

• synthetic analogue
  fragment of adrenocorticotropic hormone