Ghrelin Ghrelin Ghrelin (pronounced ), the "hunger hormone", also known as lenomorelin (INN), is a peptide hormone produced by ghrelinergic cells in the gastrointestinal tract that functions as a neuropeptide in the central nervous system. Besides regulating appetite, ghrelin also plays a significant role in regulating the distribution and rate of use of energy. When the stomach is empty, ghrelin is secreted. When the stomach is stretched, secretion stops. It acts on hypothalamic brain cells both to increase hunger, and to increase gastric acid secretion and gastrointestinal motility to prepare the body for food intake. The receptor for ghrelin, the ghrelin/growth
Counterregulatory hormone Counterregulatory hormone A counterregulatory hormone is a hormone that opposes the action of another. The action of insulin is counterregulated by glucagon, epinephrine (adrenaline), norepinephrine (noradrenaline), cortisol, and growth hormone. These counterregulatory hormones—the term is usually used in the plural—raise the level of glucose in the blood by promoting glycogenolysis, gluconeogenesis, ketogenesis, and other catabolic processes. In healthy people, counterregulatory hormones constitute a principal defense against hypoglycemia, and levels are expected to rise as the glucose falls. As an example, the exercise-induced reduction in blood glucose is counterregulated by increases in levels of epinephrine, norepinephrine, cortisol, and growth hormone. The