Ghrelin is involved in several physiological processes, including feeding and lipid accumulation, stress response; anxiety; cardiac performance; immunity and inflammation, taste sensation, reward-seeking behaviour, regulation of glucose metabolism and thermogenesis, memory, motivation and learning.

Ghrelin is a peptide hormone that typically has a serine at the third residue and relies on modification with a fatty acid to give ghrelin its functional activity. In its modified form, ghrelin is an endogenous ligand for the pituitary gland’s growth hormone receptor (GHS-R) and stimulates growth hormone release.

Ghrelin acts on the hypothalamic arcuate nucleus as an orexigenic agent to stimulate appetite. Ghrelin is produced in the stomach as a precursor peptide preproghrelin, cleaved to ghrelin. Ghrelin circulates in the blood and can cross the blood-brain barrier. Levels of ghrelin respond to fasting conditions and allow signals about the energy status to be transmitted from the peripheral organs to the central nervous system to maintain energy homeostasis.

Ghrelin is a valuable target for treating conditions such as anorexia, cachexia, sarcopenia, cardiopathy, neurodegenerative disorders, renal and pulmonary disease, gastrointestinal disorders, inflammatory disorders and metabolic syndrome.