Melanocyte-stimulating hormone
The melanocyte-stimulating hormones, known collectively as MSH, also known as melanotropins or intermedins, are a family of peptide hormones and neuropeptides consisting of α-melanocyte-stimulating hormone (α-MSH), β-melanocyte-stimulating hormone (β-MSH), and γ-melanocyte-stimulating hormone (γ-MSH) that are produced by cells in the pars intermedia of the anterior lobe of the pituitary gland.
Synthetic analogues of α-MSH, such as afamelanotide (melanotan I; Scenesse), melanotan II, and bremelanotide (PT-141), have been developed and researched.
Biosynthesis[edit]
The various forms of MSH are generated from different cleavages of the proopiomelanocortin protein, which also yields other important neuropeptides like adrenocorticotropic hormone.[1]: 554 [2]
Melanocytes in skin make and secrete MSH in response to ultraviolet light, where it increases synthesis of melanin.[3]: 441 Some neurons in arcuate nucleus of the hypothalamus make and secrete α-MSH in response to leptin;[3]: 626 [4]: 419 α-MSH is also made and secreted in the anterior lobe of the pituitary gland.[5]: 1210
Synthetic analogues of α-MSH have been developed for human use. Two of the better known are afamelanotide (melanotan I) in testing by Clinuvel Pharmaceuticals and bremelanotide by Palatin Technologies. Others include modimelanotide and setmelanotide.