Affinity, distribution, and functions of MCR subtypes

MCR Subtype Ligand Affinity Prevalent Tissue Expression Functions
MC1R α-MSH ≥ ACTH ≫ γ-MSH Melanocytes Pigmentary effects
Immune/inflammatory cells; keratinocytes; endothelial cells; glial cells Antipyretic/anti-inflammatory
MC2R ACTH Adrenal cortex Steroidogenesis
MC3R γ-MSH = ACTH ≥ α-MSH CNS Autonomic functions
Macrophages Anti-inflammatory
MC4R α-MSH = ACTH ≫ γ-MSH CNS Control of feeding and energy homeostasis; erectile activity
MC5R α-MSH ≥ ACTH > γ-MSH Exocrine glands, lymphocytes Regulation of exocrine secretions, immunoregulatory functions
  • CNS, central nervous system.