title: Metabolic effects of overnight continuous infusion of unacylated ghrelin in humans.
abstract: OBJECTIVE
  To clarify the metabolic effects of an overnight i.v. infusion of unacylated ghrelin (UAG) in humans. UAG exerts relevant metabolic actions, likely mediated by a still unknown ghrelin receptor subtype, including effects on β-cell viability and function, insulin secretion and sensitivity, and glucose and lipid metabolism.
  
  
  METHODS
  We studied the effects of a 16-h infusion (from 2100 to 1300  h) of UAG (1.0  μg/kg per h) or saline in eight normal subjects (age (mean±s.e.m.), 29.6±2.4 years; body mass index (BMI), 22.4±1.7  kg/m(2)), who were served, at 2100 and 0800  h respectively, with isocaloric balanced dinner and breakfast. Glucose, insulin, and free fatty acid (FFA) levels were measured every 20  min.
  
  
  RESULTS
  In comparison with saline, UAG induced significant (P<0.05) changes in glucose, insulin, and FFA profiles. UAG infusion decreased glucose area under the curve (AUC) values by 10% (UAG(0 - 960  min): 79.0±1.7×10(3)  mg/dl per min vs saline(0- 960  min): 87.5±3.8×10(3)  mg/dl per min) and the AUC at night by 14% (UAG(180)(-)(660  min): 28.4±0.5×10(3)  mg/dl per min vs saline(180 - 660  min): 33.2±1.1×10(3)  mg/dl per min). The overall insulin AUC was not significantly modified by UAG infusion; however, insulin AUC observed after meals was significantly increased under the exposure to UAG with respect to saline at either dinner or breakfast. The FFA AUC values were decreased by 52% under the exposure to UAG in comparison with saline (UAG(0 - 960  min): 0.3±0.02×10(3)  mEq/l per min vs saline(0 - 960  min): 0.6±0.05×10(3)  mEq/l per min).
  
  
  CONCLUSIONS
  Exposure to the i.v. administration of UAG improves glucose metabolism and inhibits lipolysis in healthy volunteers. Thus, in contrast to the diabetogenic action of AG, UAG displays hypoglycemic properties.
authors.affiliation: Division of Endocrinology, Diabetology and Metabolism, Department of Internal Medicine, Molinette Hospital, University of Turin, Corso Dogliotti 14, 10126 Turin, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Benso
authors.forename: D H
authors.initials: DH
authors.lastname: St-Pierre
authors.forename: F
authors.initials: F
authors.lastname: Prodam
authors.forename: E
authors.initials: E
authors.lastname: Gramaglia
authors.forename: R
authors.initials: R
authors.lastname: Granata
authors.forename: A J
authors.initials: AJ
authors.lastname: van der Lely
authors.forename: E
authors.initials: E
authors.lastname: Ghigo
authors.forename: F
authors.initials: F
authors.lastname: Broglio
mesh_terms: D000215:Acylation; D000328:Adult; D001786:Blood Glucose / Q000187:drug effects* / Q000378:metabolism*; D004311:Double-Blind Method; D004734:Energy Metabolism / Q000187:drug effects / Q000502:physiology; D054439:Ghrelin / Q000008:administration & dosage* / Q000378:metabolism; D006801:Humans; D007262:Infusions, Intravenous; D007328:Insulin / Q000097:blood*; D008066:Lipolysis / Q000187:drug effects / Q000502:physiology; D008297:Male; D013997:Time Factors
chemical_list: D001786:Blood Glucose; D054439:Ghrelin; D007328:Insulin