Melanocortin receptors in inflammatory disorders: pharmacology and therapeutic relevance — VialBase Research
MC1R-MC5R regulate diverse functions from pigmentation to immune modulation
- MC1R-MC5R regulate diverse functions from pigmentation to immune modulation
- MC1R involved in melanoma risk; MC2R in familial glucocorticoid deficiency
- MC3R/MC4R mutations associated with obesity and type 2 diabetes
- FDA-approved MCR agonists include bremelanotide, afamelanotide, setmelanotide
- Melanocortin receptors implicated in atopic dermatitis, MS, IBD, Alzheimer's, arthritis
- α-MSH analogs show therapeutic potential in inflammatory conditions
Summary
Comprehensive review of melanocortin receptor (MCR) pharmacology, covering MC1R through MC5R. Documents genetic polymorphisms, tissue distribution (brain, limbic system, adrenal cortex, immune cells), and disease associations. Reviews FDA-approved MCR agonists including bremelanotide (MC3R/MC4R, HSDD), afamelanotide (MC1R, erythropoietic protoporphyria), and setmelanotide (MC4R, rare genetic obesity).
Key Findings
- Five melanocortin receptors (MC1R-MC5R) with distinct tissue distribution and functions
- MC3R: energy homeostasis, appetite regulation, motivational aspects of behavior
- MC4R: appetite control, energy balance, sexual function, stress response
- Bremelanotide acts primarily on MC3R/MC4R — explaining its pro-sexual and appetite-suppressing effects
- Melanocortin system involved in numerous inflammatory conditions
- Several newer therapeutic agents targeting MCRs show advantages over current anti-inflammatory drugs
- Repository corticotropin injection (RCI) approved for sarcoidosis
Relevance to PT-141
Places PT-141/bremelanotide in the broader melanocortin receptor pharmacology landscape. Understanding that MC3R and MC4R regulate both sexual function and energy balance explains PT-141’s side effects (nausea, appetite changes) alongside its therapeutic effects (desire enhancement). The broader MCR pharmacology also suggests future therapeutic applications beyond HSDD.
Citation
Pharmacol Rev. 2025. PMID: 41002740
See Also
- Parent compound: PT-141
- Related compound: Melanotan-II