Curbing Inflammation through Endogenous Pathways: Focus on Melanocortin Peptides

Table 1

The melanocortin system.

	Melanocortin Receptors
	MC1	MC2	MC3	MC4	MC5
Endogenous agonists	αMSH=ACTH>βMSH>γMSH	ACTH	γMSH>ACTH=αMSH=βMSH	αMSH=ACTH>βMSH>γMSH	αMSH>ACTH=βMSH≫γMSH
Distribution	Skin; Melanocytes; Keratinocytes; Endothelial cells; Mucosal cells; Adipocytes; Chondrocytes; Osteoblasts; Macrophages; Monocytes; Dendritic cells; Mast cells; Neutrophils; CD8+ T cells; B Lymphocytes	Adrenal glands; Adipocyte; Osteoblasts; Dendritic cell; Chondrocyte	Hypothalamus; Macrophages; Monocytes; Dendritic cells; CD4+ T cells; B lymphocytes	Hypothalamus; Dendritic cells; Osteoblasts	Exocrine  glands; Sebocytes; Macrophages; Dendritic cells; Mast cells; Chondrocyte; CD4 T cells; B lymphocytes; NK cells
Signalling pathways	cAMP; ERK1/ERK2	cAMP	cAMP; Intracellular [Ca^2+]	cAMP	cAMP; Intracellular [Ca^2+]; Jak/STAT
Biological functions	Skin pigmentation; Inflammation; Wound healing	Steroidogenesis	Energy homeostasis Inflammation	Energy homeostasis; Food intake; Erectile function	Exocrine glands function,; Inflammation; Defensive behaviour
Role in disease/Potential use	Skin cancer; Inflammation; Alopecia areata (?); Vitiligo	Familial glucocorticoid deficiency	Inflammation; Gouty arthritis; Obesity; Tuberculosis (?)	Obesity; Cachexia; Sexual dysfunction	Seborrheic dermatitis; Acne vulgaris; Inflammation