The endocrine effects of acylated and des-acylated ghrelin

Acylated ghrelin is one of the few peptides known whose isolation and characterization follow the description of its receptor and its basic biological functions. Characterized initially for its somatotrophic properties, ghrelin was shown later to exert various effects on other important physiological functions in mammals, such as appetite, gastric acid secretion, gut motility, insulin sensitivity, adiposity, and energy expenditure. Further, ghrelin influences cardiac function, reproduction, and the immune system as well. Here we present an overview of the discovery and subsequent development of ghrelin as an important peptide hormone involved in the control of energy metabolism in humans and other mammals. Recently reported effects of acylated ghrelin on glucose/lipid uptake, de novo lipogenesis, gluconeogenesis, lipid-droplet formation, fatty acid transport into mitochondria, and mitochondrial activity are particularly emphasized and discussed.