Ghrelin Enhances Appetite and Increases Food Intake in Humans

TLDR

Ghrelin, an endogenous ligand for the growth hormone secretagogue receptor produced mainly in the stomach, has been shown to increase food intake and weight gain in rodents, but its role in human appetite had not been established. The study aimed to determine whether intravenous ghrelin alters appetite and food consumption in healthy adults. A randomized, double‑blind, cross‑over trial administered 5.0 pmol kg⁻¹ min⁻¹ intravenous ghrelin or saline to nine healthy volunteers. Intravenous ghrelin produced a significant 28 % rise in buffet food intake, heightened appetite scores, and did not alter gastric emptying, establishing it as the first circulating hormone to stimulate human food intake and highlighting its potential role in energy balance.

Abstract

Ghrelin is a recently identified endogenous ligand for the growth hormone secretagogue receptor. It is synthesized predominantly in the stomach and found in the circulation of healthy humans. Ghrelin has been shown to promote increased food intake, weight gain and adiposity in rodents. The effect of ghrelin on appetite and food intake in man has not been determined. We investigated the effects of intravenous ghrelin (5.0 pmol/kg/min) or saline infusion on appetite and food intake in a randomised double-blind cross-over study in nine healthy volunteers. There was a clear-cut increase in energy consumed by every individual from a free-choice buffet (mean increase 28 ± 3.9%, p<0.001) during ghrelin compared with saline infusion. Visual analogue scores for appetite were greater during ghrelin compared to saline infusion. Ghrelin had no effect on gastric emptying as assessed by the paracetamol absorption test. Ghrelin is the first circulating hormone demonstrated to stimulate food intake in man. Endogenous ghrelin is a potentially important new regulator of the complex systems controlling food intake and body weight.