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.