Ghrelin is a hormone produced by the enteroendocrine cells of the stomach. It is responsible for:

Ghrelin is a hormone produced by the enteroendocrine cells of the stomach, and to lesser extent by the placenta, pituitary, and hypothalamus. In humans, ghrelin has been shown to be a potent growth hormone secretagogue and appetite stimulant. Good to know: Increased ghrelin levels seen in, Fasting Individuals consuming low calorie diets Chronic strenuous exercise Cancer anorexia Anorexia nervosa Prader-Willi syndrome Decreased ghrelin levels seen in, During meals Obesity Ghrelin levels are decreased in obese individuals. Ref: Molina P.E. (2010). Chapter 10. Endocrine Integration of Energy & Electrolyte Balance. In P.E. Molina (Ed), Endocrine Physiology, 3e.