Melanocortin receptor

Updated on Nov 13, 2023

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Melanocortin receptor top 5 facts

Melanocortin receptors are members of the rhodopsin family of 7-transmembrane G protein-coupled receptors.

There are five known members of the melanocortin receptor system each with differing specificities for melanocortins:

MC1R. MC1R is associated with pigmentation genetics.

MC2R. MC2R is also known as the ACTH receptor or corticotropin receptor because it is specific for ACTH alone.

MC3R. MC3R

MC4R. Defects in MC4R are a cause of autosomal dominant obesity, accounting for 6% of all cases of early-onset obesity.

MC5R. MC5R

These receptors are inhibited by endogenous inverse agonists agouti signalling peptide and agouti-related peptide, and activated by synthetic (i.e. afamelanotide) and endogenous agonist melanocyte-stimulating hormones.

Selective ligands

Several selective ligands for the melanocortin receptors are known, and some synthetic compounds have been investigated as potential tanning, anti-obesity and aphrodisiac drugs, with tanning effects mainly from stimulation of MC₁, while anorectic and aphrodisiac effects appear to involve both MC₃ and MC₄. MC₁, MC₃ and MC₄ are widely expressed in the brain, and are also thought to be responsible for effects on mood and cognition.