Ghrelin: Implications in Pediatric Endocrinology

Abstract

Ghrelin, a 28 amino-acid acylated peptide predominantly produced by the stomach, displays strong growth hormone (GH)-releasing activity mediated by the hypothalamus-pituitary GH Secretagogue (GHS) receptors which had been shown to be specific for a family of synthetic, orally active GHS. Ghrelin and GHS show other endocrine and nonendocrine actions including orexigenic effects and influence on gastro-entero-pancreatic functions. Ghrelin manages the neuroendocrine and metabolic response to starvation. The study of ghrelin secretion as function of age and gender as well as the study of the endocrine and nonendocrine effects of ghrelin and its analogues in physiological and pathological conditions will likely provide critical information about the role of ghrelin and the potential perspectives of its analogues in 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. GHS analogues acting as agonists or antagonists on appetite could represent new drug intervention in eating disorders. GHS could therefore represent a reliable provocative test for the diagnosis of GH deficiency but as orally active growth-promoting agents they are not comparable with rhGH in terms of efficacy.