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[Regulation of appetite by melanocortin and its receptors]

Y Mori1

  • 1Genetique des Maladies Multifactorielles, Institut de Biologie de Lille-Institut Pasteur de Lille.

Nihon Rinsho. Japanese Journal of Clinical Medicine
|March 28, 2001
PubMed

Insights

Melanocortins, like alpha-MSH, regulate appetite via the MC4R receptor. Genetic mutations in POMC or MC4R are linked to obesity and other health issues, highlighting their critical role in human appetite control.

Area of Science:

  • Endocrinology
  • Genetics
  • Neuroscience

Background:

  • Alpha, beta, and gamma-melanocyte-stimulating hormone (MSH) and adrenocorticotropic hormone (ACTH) originate from proopiomelanocortin (POMC).
  • Alpha-MSH regulates appetite and energy expenditure through the central melanocortin 4 receptor (MC4R), primarily in the hypothalamus.
  • MC4R antagonists stimulate appetite, while MC4R knockout mice exhibit obesity and reduced energy expenditure.

Purpose of the Study:

  • To investigate the role of melanocortins and their receptors in human appetite regulation.
  • To explore the genetic basis of obesity related to the POMC and MC4R genes.

Main Methods:

  • Review of existing literature on melanocortin signaling and obesity genetics.
  • Analysis of POMC gene mutations in families with obesity, red hair, and adrenal dysfunction.
  • Examination of MC4R gene mutations in obese patient cohorts.

Main Results:

  • POMC gene mutations in both alleles cause obesity, red hair, and adrenal dysfunction due to deficiencies in alpha-MSH and ACTH.
  • Heterozygous MC4R gene mutations are identified in 4% of morbidly obese patients.
  • Agouti-related peptide (AgRP) acts as an antagonist to MC3R and MC4R, potentially inhibiting alpha-MSH.

Conclusions:

  • Melanocortin signaling pathways, particularly involving alpha-MSH and MC4R, are crucial for human appetite regulation.
  • Genetic variations in POMC and MC4R are significant contributors to human obesity.
  • Dysregulation of the melanocortin system has profound implications for metabolic health.

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