| MCRs type | Distribution | Function | Agonists | Signaling system | References |
| MC1R | | Pigmentation, regulation of skin physiology, anti-inflammation, pain | α-MSH, β-MSH, γ-MSH and its analogues (MT I, MT II) | cAMP-PKA pathway, Ca++ signaling |
[1, 3, 4, 29–32] | MC2R | Adrenal cortex, murine adipocytes, skin, melanoma cells | Adrenal steroids secretion | ACTH | cAMP-PKA pathway | [1, 3, 4] | MC3R | CNS, stomach, kidneys, heart, gut, thymus, placenta | Feeding, energy homeostasis and anti-inflammation | ACTH and γ-MSH | cAMP-PKA, MAPK and IP/Ca++ signaling | [1, 3, 29, 33] | MC4R | CNS | Anti-inflammatory, control of feeding and sexual behaviors, energy homeostasis | α-MSH, ACTH | cAMP-PKA and MAPK | [1, 3, 31, 33] | MC5R | CNS and many peripheral tissues, exocrine glands, spleen, skin, lung, sexual organs, adipose tissues. | Exocrine secretion, lipolysis, regulation of body temperature | ACTH(1–24), α-MSH, MT I & MT II | cAMP-PKA and Jak/STAT phosphorylation pathway |
[1, 3, 29, 33] |
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