Features
Afamelanotide is a potent, linear synthetic analog of the naturally occurring peptide hormone α-melanocyte-stimulating hormone (α-MSH).Modified to have a stronger binding affinity to melanocortin- 1 receptor (MC1R) and a smaller disassociation constant, afamelanotide has a longer half-life and subsequently exerts longer pharmacologic activity than its parent hormone.
Uses
Melanotan 1 is a highly potent melanotropin with extended biological activity and resistance to enzymatic degredation by serum enzymes. [Nle4, D-Phe7]-α-Melanocyte Stimulating Hormone trifluoroacetate salt has been used to detect its effect on O2 consumption and CO2 production in C57BL/6 mice. It is also used to determine its effect on leptin secretion in the primary cultures of differentiated adipocytes.
Definition
ChEBI: Afamelanotide is a polypeptide comprising of 13 amino acids which is an analogue of alpha-melanocyte stimulating hormone. It is approved as a dermatologic drug for the prevention of phototoxicity in adult patients with erythropoietic protoporphyria. It has a role as a dermatologic drug.
Origin
Melanotan 1, an alpha MSH analog (Nle4DPhe7-Melanocyte-Stimulating Hormone), is a potent melanocortin developed in the 1980s. Melanotan 2 is a shorter cyclic variant of Melanotan 1 produced in the 1990s. Melanotan 2 was found to increase skin pigmentation at lower cumulative doses than Melanotan 1. However, in clinical trials it was found to have more side effects including nausea somnolence and penile erections[1].
References
[1] Robert T Dorr. “Effects of a superpotent melanotropic peptide in combination with solar UV radiation on tanning of the skin in human volunteers.” Archives of dermatology 140 7 (2004): 827–35.
General Description
[Nle4, D-Phe7]-α-melanocyte stimulating hormone is a potent analogue of α;-melanocyte-stimulating hormone (α -MSH). αMSH is a tridecapeptide, mostly produced by the cells in the brain, pituitary and in circulation.
Biochem/physiol Actions
[Nle4, D-Phe7]-α-melanocyte stimulating hormone is 100 times more potent than α-MSH in stimulating melanoma tyrosinase, which is a rate limiting enzyme in melanin biosynthesis and is 26 times as potent as α-MSH in S91adenylate cyclase assay. α –MSH has an essential role to play in melanin production in animals. It also regulates development of several skin diseases, including cutaneous inflammation and hyper-proliferative skin diseases.
Side effects
The TGA has previously warned consumers against the use of Melanotan-I and Melanotan-II for tanning and weight loss. Side-effects include darkened skin, increased moles and freckles, nausea, vomiting, loss of appetite, flushing of the face, involuntary stretching and yawning, and spontaneous erections.
