ACTH
Category: Hormones · Last updated
ACTH (Adrenocorticotropic Hormone, also called corticotropin) is a 39-amino-acid peptide hormone secreted by corticotroph cells of the anterior pituitary gland in response to hypothalamic CRH. It binds the melanocortin-2 receptor (MC2R) on adrenocortical cells, stimulating cortisol production.
Structure
The full ACTH(1-39) sequence is cleaved from the larger precursor pro-opiomelanocortin (POMC). Several short fragments retain partial biological activities:
- ACTH(1-24) · retains full steroidogenic activity (Synacthen / Cortrosyn)
- ACTH(4-10) · retains neurotropic activity but lacks corticotropin activity
- ACTH(4-7) · the minimal sequence for neurotropic activity
Relevance to research peptides
- Semax · synthetic heptapeptide based on ACTH(4-7) with a C-terminal Pro-Gly-Pro extension. The extension stabilizes the molecule and eliminates corticotropin activity, leaving neurotropic activity intact.