Role of ghrelin in the regulation of appetite in children.

Ghrelin, the new 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 on insulin secretion and glucose metabolism, orexigenic effect and modulatory activity on the neuroendocrine and metabolic response to starvation, influence on exocrine gastro-entero-pancreatic functions, cardiovascular activities and modulation of cell proliferation and apoptosis. The wide spectrum of ghrelin action requires further studies to provide critical information on the role of ghrelin and the potential perspectives of its analogues in the clinical practice. This point is of particular interest in the field of pediatric endocrinology and metabolism because the ghrelin story started focusing on GH deficiency and is now extending to aspects that once again are of major relevance such as obesity and eating disorders, regulation of the hypothalamus-pituitary-adrenal and gonadal axis. More studies are needed to evaluate the real impact of ghrelin in different non endocrine processes and the possible use of ghrelin analogues in different diseases condition.