Ghrelin, the same peptide for different functions: player or bystander?
Ghrelin is a recently discovered brain-gut peptide with two main physiological actions: growth hormone secretagogue activity and food intake inducer. Although its production is prevalently gastric, ghrelin is widely expressed in several tissues, where it might therefore act as a paracrine or autocrine factor. It is becoming clear that ghrelin is much more than a simple growth hormone secretagogue. In addition to its formerly envisaged role, ghrelin has other activities including stimulation of pituitary hormones secretion, modulation of food intake and control of energy metabolism, regulation of gastric and pancreatic activity, and cardiovascular and hemodynamic activities. In addition, modulation of cartilage and bone homeostasis, sleep and behavioral influences, and modulation of the immune system, as well as effects on cell proliferation, are other relevant actions of ghrelin. Thus, the peptide appears to be an important component of an integrated multifaceted regulatory system. In this review, we summarize several aspects of ghrelin biology and attempt to inform the reader with information regarding unexpected functions of this gastric peptide.
Lago
Francisca
F
Santiago University Clinical Hospital, Research Area, Molecular and Cellular Cardiology Laboratory 1, 15705 Santiago de Compostela, Spain.
Gonzalez-Juanatey
José Ramón
JR
Casanueva
Felipe F
FF
Gómez-Reino
Juan
J
Dieguez
Carlos
C
Gualillo
Oreste
O
D000215:Acylation; D000595:Amino Acid Sequence; D000818:Animals; D001066:Appetite; D001519:Behavior; D001842:Bone and Bones; D002319:Cardiovascular System; D002356:Cartilage; D002455:Cell Division; D004734:Energy Metabolism; D054439:Ghrelin; D013006:Growth Hormone / Q000378:metabolism; D006706:Homeostasis; D006801:Humans; D007109:Immunity; D051379:Mice; D018345:Mice, Knockout; D008969:Molecular Sequence Data; D010179:Pancreas / Q000502:physiology; D036361:Peptide Hormones / Q000737:chemistry / Q000172:deficiency / Q000502:physiology*; D043562:Receptors, G-Protein-Coupled / Q000172:deficiency; D054440:Receptors, Ghrelin; D012890:Sleep; D013270:Stomach / Q000502:physiology; D014018:Tissue Distribution
D054439:Ghrelin; D036361:Peptide Hormones; D043562:Receptors, G-Protein-Coupled; D054440:Receptors, Ghrelin; D013006:Growth Hormone