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| Names | |
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| IUPAC name N-acetyl-L-seryl-L-tyrosyl-L-seryl-L-methionyl-L-α-glutamyl-L-histidyl-L-phenylalanyl-L-arginyl-L-tryptophylglycyl-L-lysyl-L-prolyl-L-valinamide | |
| Other names alpha-MSH, α-melanocortin, α-melanotropin, α-intermedin; Ac-Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH2 | |
| Identifiers | |
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| ChEBI | |
| ChEMBL | |
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| UNII | |
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| Properties | |
| C77H109N21O19S | |
| Molar mass | 1664.884 g/mol |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
α-Melanocyte-stimulating hormone (α-MSH) is anendogenouspeptide hormone andneuropeptide of themelanocortin family, with atridecapeptidestructure and theamino acid sequence Ac-Ser-Tyr-Ser-Met-Glu-His-Phe-Arg-Trp-Gly-Lys-Pro-Val-NH2. It is the most important of themelanocyte-stimulating hormones (MSHs) (also known as melanotropins) in stimulatingmelanogenesis, a process that inmammals (includinghumans) is responsible forpigmentation primarily of thehair andskin. It also plays a role infeeding behavior,energy homeostasis,sexual activity, and protection againstischemia andreperfusion injury.[1]
α-MSH is anon-selectivefull agonist of themelanocortin receptorsMC1 (Ki = 0.230 nM),MC3 (Ki = 31.5 nM),MC4 (Ki = 900 nM), andMC5 (Ki = 7160 nM), but notMC2 (which is exclusive foradrenocorticotropic hormone (ACTH)).[2] Activation of the MC1 receptor is responsible for its effect on pigmentation, whereas its regulation of appetite, metabolism, and sexual behavior is mediated through both the MC3 and MC4 receptors.
It is generated as aproteolyiccleavage product from ACTH (1-13), which is in turn a cleavage product ofproopiomelanocortin (POMC).
A fewsyntheticanalogues of α-MSH have been investigated asmedicinaldrugs due to theirphotoprotective effects againstultraviolet (UV) radiation from the sun. They includeafamelanotide (melanotan) andmelanotan II, the former of which has been approved as a treatment to reducephotosensitivity inerythropoietic protoporphyria in theUnited States.[3]Bremelanotide, another analogue of α-MSH, is available in the United States not as a photoprotective agent, but for the treatment ofhypoactive sexual desire disorder in premenopausal women.[4] All of these drugs have significantly greaterpotencies than α-MSH, along with improvedpharmacokinetics and distinctiveselectivity profiles.
