title: Jejunal linoleic acid infusions require GLP-1 receptor signaling to inhibit food intake: implications for the effectiveness of Roux-en-Y gastric bypass.
abstract: Roux-en-Y gastric bypass surgery results in sustained decreases in food intake and weight loss. A key component is likely the direct delivery of nutrients to the jejunum and resulting changes in levels of gut peptide secretion. Prior work modeling this aspect of the surgery has shown that small-volume, prolonged jejunal infusions of linoleic acid (LA) produce sustained decreases in food intake and weight loss. LA infusions also significantly elevate plasma glucagon-like peptide-1 (GLP-1) levels. To assess a role for the increased circulating GLP-1 in the feeding suppression, we examined the effect of prolonged peripheral minipump administration of the GLP-1 receptor antagonist exendin 9-39 (Ex 9) on the feeding suppression produced by jejunal LA. Using a 2 × 2 design, we infused either saline or LA in the jejunum (7 h/day, 11.4 kcal) for 5 days with a subset of animals from each group receiving either saline or Ex 9 (25 pmol·kg(-1)·min(-1)) continuously via a minipump. The antagonist alone had no effect on food intake. LA reduced daily food intake greatly in excess of the kilocalories infused. Ex 9 completely blocked the feeding suppression produced by the jejunal LA infusion. Ex 9 also attenuated the increase in plasma GLP-1 induced by jejunal LA infusions. These data demonstrate that endogenous GLP-1 receptor signaling is necessary for the reduction in food intake produced by jejunal LA infusions. Whether increased secretion of additional gut peptides is also necessary for such suppressions remains to be determined.
authors.affiliation: Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA. mdailey5@jhmi.edu
authors.forename: Megan J
authors.initials: MJ
authors.lastname: Dailey
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Moghadam
authors.forename: Timothy H
authors.initials: TH
authors.lastname: Moran
mesh_terms: D000818:Animals; D001069:Appetite Regulation / Q000187:drug effects* / Q000502:physiology; D015536:Down-Regulation / Q000187:drug effects; D004333:Drug Administration Routes; D004435:Eating / Q000187:drug effects; D015390:Gastric Bypass; D000067757:Glucagon-Like Peptide-1 Receptor; D007263:Infusions, Parenteral; D007583:Jejunum / Q000187:drug effects; D019787:Linoleic Acid / Q000008:administration & dosage* / Q000494:pharmacology; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D018027:Receptors, Glucagon / Q000097:blood / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology; D016896:Treatment Outcome
chemical_list: C000593835:Glp1r protein, rat; D000067757:Glucagon-Like Peptide-1 Receptor; D018027:Receptors, Glucagon; D019787:Linoleic Acid