Ghrelin: A new hormone with endocrine and non-endocrine activities

Ghrelin, the new and recently discovered hormone, is a 28 amino-acid acylated peptide predominantly produced by the stomach, characterized by a strong GH-releasing activity mediated by the hypothalamic-pituitary GH Secretagogues (GHSs) receptors. Ghrelin and GHSs, acting on central and peripheral receptors, exert other actions such as: stimulation of ACTH and prolactin secretion; influence insulin secretion and glucose metabolism; have an orexigenic effect and modulatory activity on the neuroendocrine and metabolic response to starvation; influencing exocrine gastro-entero-pancreatic functions; influencing cardiovascular activities and modulation of cell proliferation and apoptosis. With the discovery of ghrelin and the characterization of these GH-independent biological activities, we have to pay more attention to these molecules as candidate drugs for the treatment of pathophysiological conditions including those unrelated to GH secretion disorders.