Ghrelin, a widespread hormone: insights into molecular and cellular regulation of its expression and mechanism of action.

The recent discovery of ghrelin, the endogenous ligand for the growth hormone secretagogue receptor, is the result of almost 25 years of research by many groups all around the world, and represents a milestone in our understanding of growth hormone secretion and energy homeostasis. This minireview is focused on recent studies on ghrelin, pointing out the cellular and molecular mechanisms involved in the gene expression of ghrelin since recent studies have unequivocally shown that ghrelin biological activity is dependent on a peculiar post-translational processing. Major interest in this peptide derived from the fact that, in addition to other effects, it is involved in the regulation of energy balance by inducing weight gain and reducing fat utilization. These activities are likely mediated by a CNS network of cells that is also modulated by other hormones such as leptin. Ghrelin has emerged as a premeal initiation factor that informs CNS about the status of the energy balance. The development of ghrelin analogs, agonists and antagonists, appears as a suitable approach for possible therapeutic intervention in a variety of disease states linked to alterations in body weight homeostasis.