Proopiomelanocortin (POMC) is a precursor protein that, when cleaved, gives rise to several hormones: ACTH and the melanocyte-stimulating hormones (α-, β- and γ-MSH). They all share a core sequence recognised by the melanocortin receptors.
Each receptor has its role. MC1R, on melanocytes, controls melanin production. MC2R is the ACTH receptor in the adrenal gland. MC3R and MC4R, in the brain, take part in energy balance and sexual function. MC5R is found in exocrine glands.
Synthetic analogues differ in selectivity: afamelanotide (Melanotan I) is relatively selective for MC1R; Melanotan II activates several receptors at once; bremelanotide (PT-141) acts on MC4R and MC3R. The tripeptide KPV, the tail end of α-MSH, is studied for its anti-inflammatory activity.
Within the same family, small sequence differences change which receptors are activated and, with them, the effect profile. Melanocortins are the textbook example of subtype selectivity.
Related terms
Learn it in depth at the Peptide University
- Somatotropic, neuro and others (11–15) · Module 14
- The melanocortin system: pigmentation and PT-141 · Module 6
- Neuroimmunomodulation: VIP, α-MSH, KPV and ARA-290 · Module 12
- Complementary monographs (16–20) · Module 14
- G protein-coupled receptors: desensitization and tolerance · Module 2
Related catalogue compounds
Definition for educational and scientific purposes. It is not medical advice or a recommendation for use. NeoPeptidos products are sold labelled for research use only (RUO).