Ghrelin Appetite Hormone in Health and Disease

Abstract

Ghrelin is a 28‐amino‐acid appetite hormone and has numerous physiological roles in appetite modulation, glucose and lipid metabolisms, gastrointestinal, cardiovascular, reproductive, pulmonary and bone systems or immune modulation and cell proliferation. Recent studies implicate ghrelin in the pathogenesis of many diseases, including obesity, Prader–Willi syndrome, cachexia, Anorexia nervosa, cardiovascular diseases, reproductive disorders, diabetes and inflammatory bowel disease. Understanding the pharmacology and physiology of ghrelin agonists and antagonists and investigation of the role of appetite hormones in the regulation of food intake in humans will allow us to find potential therapeutic managements for the treatment of many of those diseases.

Key Concepts:

  • Ghrelin, a 28 amino‐acid peptide hormone that was discovered as an endogenous ligand for the growth hormone secretagogue‐receptor (GHS‐R), has two circulating forms: acylated and desacyl. The acylated form is essential for ghrelin's biological activity through GHS‐R. It is produced primarily in the stomach, hypothalamus, pituitary, intestine, kidney, heart, lung, gonads and placenta.

  • Ghrelin is peripheral circulating appetite hormone, acts as a physiological hunger signal. Its secretion and blood levels rise during fasting and fall after eating. It stimulates appetite and increases food intake via secretion of GH. Repeated administration of ghrelin results in decreased energy expenditure; thus, increasing body fat and weight.

  • Ghrelin have major biological functions in glucose and lipid metabolism and main physiological systems such as gastrointestinal, cardiovascular, reproductive, pulmonary, bone and immune.

  • Ghrelin appears to be involved in the pathophysiological mechanisms of several human disorders, including obesity, Prader–Willi syndrome, cachexia, Anorexia nervosa, cardiovascular diseases, reproductive disorders, diabetes and inflammatory bowel disease.

Keywords: Ghrelin; health; appetite; gastrointestinal; cardiovascular; pulmonary; immune; reproductive; bone; metabolism; disease

Figure 1.

Schematic presentation of the physiological effects of ghrelin on the human body.

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Further Reading

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Itoh T, Nagaya N, Yoshikawa M et al. (2004) Elevated plasma ghrelin level in underweight patients with chronic obstructive pulmonary disease. American Journal of Respiratory and Critical Care Medicine 170(8): 879–882.

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Williams G and Frühbeck Gema (eds) (2009) Obesity: Science to Practice. Oxford: John Wiley & Sons, Ltd.

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Caylak, Emrah(Jul 2012) Ghrelin Appetite Hormone in Health and Disease. In: eLS. John Wiley & Sons Ltd, Chichester. http://www.els.net [doi: 10.1002/9780470015902.a0024164]