What is the Origin of Melanocortin 4 Receptor?

The Melanocortin Receptor family was identified through research into the physiological roles of pituitary-derived melanocyte-stimulating hormones (MSH) and their influence on pigmentation and other systemic functions. The MC4R was specifically identified for its distinct and profound role in the neuroendocrine control of feeding behavior. The name reflects its classification as the fourth receptor subtype for melanocortin peptides, and its study has been pivotal in understanding the molecular basis of obesity.

What is the Mechanism of Melanocortin 4 Receptor?

The MC4R is dynamically regulated by two opposing endogenous ligands: it is tonically inhibited by the Agouti-related peptide (AgRP) and is strongly activated by the $alpha$-Melanocyte-Stimulating Hormone ($alpha$-MSH), a derivative of the POMC precursor. Activation by $alpha$-MSH triggers an intracellular signaling cascade, primarily through the cAMP pathway, which ultimately leads to a powerful suppression of appetite and a sustained increase in resting energy expenditure. Conversely, blockade by AgRP promotes robust feeding behavior.

Melanocortin 4 Receptor ∞ Area ∞ Library 3

Melanocortin 4 Receptor

Meaning

The Melanocortin 4 Receptor (MC4R) is a G-protein coupled receptor (GPCR) that is densely expressed within the central nervous system, predominantly in key hypothalamic nuclei, and functions as a critical regulator of energy homeostasis, satiety, and sexual behavior. This receptor is a central component of the melanocortin system, acting as a metabolic sensor that integrates signals of energy status to modulate both food intake and overall energy expenditure. Its proper signaling is essential for the physiological maintenance of a healthy body weight and metabolic balance.