MC4R A gene on chromosome 18q22 that encodes a receptor for alpha, beta and gamma melanocyte stimulating hormone (MSH), the activity of which is mediated by G protein-activated adenylate cyclase and expressed in the brain, placenta and gut.
Defects in MC4R are linked to obesity.
melanocortin 4 receptor (MC4R) A cell receptor that is strongly stimulated by the alpha melanocyte-stimulating hormone-a peptide that produces a sense of fullness after eating. Mutations of the gene that codes for MC4R are commonly associated with severe uncontrollable overeating and pathological obesity. Such mutations can be found in nearly 6 per cent of people with a life-long history of obesity.