Ghrelin — a multifunctional activities hormone

Abstract

Ghrelin was isolated in 1999 from rat stomach. Ghrelin is identified as the 28-amino-acid peptide. It is a hormone secreted into the circulation from the stomach but also synthestised in a number of tissues, suggesting both endocrine and paracrine effects. Ghrelin recently identified as the natural ligand for the growth hormone secretagogue receptor, has multiple activities in addition to stimulation of GH secretion, including stimulation of feeding and weight gain. These include: prolactin and ACTH secretion; an increase in appetite; a diabetogenic effect on carbohydrate metabolism; positive inotropic effects on heart; vasodilatation; and effects on cell proliferation. The possibility of chronic manipulation of the ghrelin system on body weight, growth and appetite remains an exciting new field of exploration. Ghrelin has been reported to regulate energy homeostasis. Ghrelin is mostly produced by the stomach, although its production has been proved in various tissues.