title: Ability of GLP-1 to decrease food intake is dependent on nutritional status.
abstract: Gut-derived glucagon like peptide-1 (GLP-1) acts in the postprandial period to stimulate insulin secretion and inhibit gastrointestinal motor and secretory function; whether endogenous peripheral GLP-1 inhibits food intake is less clear. We hypothesized that GLP-1 inhibits food intake in the fed, but not fasted, state. There is evidence that GLP-1 acts via stimulation of vagal afferent neurons (VAN); we further hypothesized that the satiating effects of endogenous GLP-1 in the postprandial period is determined either by a change in GLP-1 receptor (GLP-1R) expression or localization to different cellular compartments in VAN.
  
  
  METHODS
  Food intake was recorded following administration of GLP-1 (50μg/kg or 100μg/kg) or saline (IP) in Wistar rats fasted for 18h or fasted then re-fed with 3g chow. GLP-1R protein expression and localization on VAN were determined by immunocytochemistry and immunoblots in animals fasted for 18h or fasted then re-fed for 40min. GLP-1R mRNA level was detected in animals fasted for 18h or fasted and re-fed ad libitum for 2h.
  
  
  RESULTS
  GLP-1 (100μg/kg) significantly reduced 40min food intake by 38% in re-fed but not fasted rats (p<0.05). GLP-1R mRNA or protein levels in VAN were unchanged in re-fed compared to fasted rats. However, GLP-1R localization to the plasma membrane was significantly increased in VAN by feeding.
  
  
  CONCLUSIONS
  Feeding changes the ability of peripheral GLP-1 to inhibit food intake. GLP-1Rs are trafficked to the plasma membrane in response to a meal. GLP-1 may play a role in regulating food intake in the postprandial period.
authors: Dept. of Anatomy, Physiology and Cell Biology, UC Davis School of Veterinary Medicine, Davis, CA 95616, USA; AgroParisTech, UMR914 Nutrition Physiology and Ingestive Behavior, Paris 75005, France.
authors: Charlotte C
authors: CC
authors: Ronveaux
authors: Dept. of Anatomy, Physiology and Cell Biology, UC Davis School of Veterinary Medicine, Davis, CA 95616, USA.
authors: Guillaume
authors: G
authors: de Lartigue
authors: Dept. of Anatomy, Physiology and Cell Biology, UC Davis School of Veterinary Medicine, Davis, CA 95616, USA. Electronic address: heraybould@ucdavis.edu.
authors: Helen E
authors: HE
authors: Raybould
mesh_terms: D000818:Animals; D004435:Eating / Q000187:drug effects* / Q000502:physiology; D005215:Fasting / Q000502:physiology*; D052216:Glucagon-Like Peptide 1 / Q000494:pharmacology*; D000067757:Glucagon-Like Peptide-1 Receptor; D008297:Male; D009474:Neurons / Q000378:metabolism; D009620:Nodose Ganglion / Q000378:metabolism; D009752:Nutritional Status; D019518:Postprandial Period / Q000502:physiology*; D051381:Rats; D017208:Rats, Wistar; D018027:Receptors, Glucagon / Q000378:metabolism
chemical_list: C000593835:Glp1r protein, rat; D000067757:Glucagon-Like Peptide-1 Receptor; D018027:Receptors, Glucagon; D052216:Glucagon-Like Peptide 1
keywords: Food intake; Glucagon-like-peptide-1; Receptor trafficking; Vagal afferent neurons