title: GLP-1 (9-36) amide metabolite suppression of glucose production in isolated mouse hepatocytes.
abstract: The glucoincretin hormone glucagon-like peptide-1 (GLP-1) augments glucose-stimulated insulin secretion and is in use as an effective treatment for diabetes. However, after its secretion from the intestine, the insulinotropic GLP-1 (7-36) amide hormone is rapidly inactivated by enzymatic cleavage by the diaminopeptidyl peptidase-4 giving rise to GLP-1 (9-36) amide. Inasmuch as most of the circulating GLP-1 is in the form of the metabolite GLP-1 (9-36) amide it has been suggested that it has insulin-like actions on peripheral insulin-sensitive tissues. In earlier studies, infusions of GLP-1 (9-36) amide in obese insulin-resistant subjects showed a marked suppression of hepatic glucose production. However, it remained uncertain whether the effects on glucose production were due to direct effects on hepatocytes, involved central or portal vein-mediated actions, or were mediated by insulin secretion. Here we show that GLP-1 (9-36) amide directly suppresses glucose production in isolated mouse hepatocytes ex vivo independent of the GLP-1 receptor. These findings support direct insulinomimetic actions of the GLP-1 metabolite on gluconeogenesis in hepatocytes that are independent of insulin action and the GLP-1 receptor, and suggest that GLP-1 (9-36) amide-based peptides might present a novel therapy for the treatment of excessive hepatic glucose production in individuals with insulin-resistant diabetes.
authors.affiliation: Laboratory of Molecular Endocrinology, Massachusetts General Hospital, Boston, USA.
authors.forename: E
authors.initials: E
authors.lastname: Tomas
authors.forename: V
authors.initials: V
authors.lastname: Stanojevic
authors.forename: J F
authors.initials: JF
authors.lastname: Habener
mesh_terms: D000577:Amides / Q000378:metabolism*; D000818:Animals; D002469:Cell Separation; D005786:Gene Expression Regulation / Q000187:drug effects; D005934:Glucagon / Q000494:pharmacology; D052216:Glucagon-Like Peptide 1 / Q000378:metabolism* / Q000494:pharmacology; D000067757:Glucagon-Like Peptide-1 Receptor; D005943:Gluconeogenesis / Q000187:drug effects / Q000235:genetics; D005947:Glucose / Q000096:biosynthesis*; D005952:Glucose-6-Phosphatase / Q000378:metabolism; D022781:Hepatocytes / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D010729:Phosphoenolpyruvate Carboxykinase (GTP) / Q000378:metabolism; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D018027:Receptors, Glucagon / Q000235:genetics / Q000378:metabolism
chemical_list: D000577:Amides; C000593834:Glp1r protein, mouse; D000067757:Glucagon-Like Peptide-1 Receptor; D012333:RNA, Messenger; D018027:Receptors, Glucagon; D052216:Glucagon-Like Peptide 1; D005934:Glucagon; D005952:Glucose-6-Phosphatase; D010729:Phosphoenolpyruvate Carboxykinase (GTP); D005947:Glucose