Ghrelin in the control of energy, lipid, and glucose metabolism

Abstract

The discovery of ghrelin as the endogenous ligand for the growth hormone secretagogue receptor (GHS-R) led to subsequent studies characterizing the endogenous action of this gastrointestinal hormone. Accordingly, exogenous administration of ghrelin was found to increase food intake and adiposity in a variety of species, including rodents, nonhuman primates, and humans. Later work supported these findings and confirmed that ghrelin acts through hypothalamic neurons to mediate its effects on energy metabolism. Ghrelin acts specifically through GHS-R to promote a positive energy balance as demonstrated by loss of ghrelin action after pharmacological blockade or genetic deletion of GHS-R. More recently, ghrelin was found to be a mediator of glucose metabolism and acts to inhibit insulin secretion from pancreatic β-cells. Together, the literature highlights a predominant role of ghrelin in regulating energy and glucose metabolism.