Exendin-4 increases blood glucose levels acutely in rats by activation of the sympathetic nervous system.

Published

Journal Article

Exendin-4 (Ex-4), an agonist of the glucagon-like peptide-1 receptor (GLP-1R), shares many of the actions of GLP-1 on pancreatic islets, the central nervous system (CNS), and the gastrointestinal tract that mediates glucose homeostasis and food intake. Because Ex-4 has a much longer plasma half-life than GLP-1, it is an effective drug for reducing blood glucose levels in patients with type 2 diabetes mellitus (T2DM). Here, we report that acute administration of Ex-4, in relatively high doses, into either the peripheral circulation or the CNS, paradoxically increased blood glucose levels in rats. This effect was independent of the insulinotropic and hypothalamic-pituitary-adrenal activating actions of Ex-4 and could be blocked by a GLP-1R antagonist. Comparable doses of GLP-1 did not induce hyperglycemia, even when protected from rapid metabolism by a dipeptidyl peptidase IV inhibitor. Acute hyperglycemia induced by Ex-4 was blocked by hexamethonium, guanethidine, and adrenal medullectomy, indicating that this effect was mediated by sympathetic nervous system (SNS) activation. The potency of Ex-4 to elevate blood glucose waned with chronic administration such that after 6 days the familiar actions of Ex-4 to improve glucose tolerance were evident. These findings indicate that, in rats, high doses of Ex-4 activate a SNS response that can overcome the expected benefits of this peptide on glucose metabolism and actually raise blood glucose. These results have important implications for the design and interpretation of studies using Ex-4 in rats. Moreover, since there are many similarities in the response of the GLP-1R system across mammalian species, it is important to consider whether there is acute activation of the SNS by Ex-4 in humans.

Full Text

Duke Authors

Cited Authors

  • Pérez-Tilve, D; González-Matías, L; Aulinger, BA; Alvarez-Crespo, M; Gil-Lozano, M; Alvarez, E; Andrade-Olivie, AM; Tschöp, MH; D'Alessio, DA; Mallo, F

Published Date

  • May 2010

Published In

Volume / Issue

  • 298 / 5

Start / End Page

  • E1088 - E1096

PubMed ID

  • 20197503

Pubmed Central ID

  • 20197503

Electronic International Standard Serial Number (EISSN)

  • 1522-1555

International Standard Serial Number (ISSN)

  • 0193-1849

Digital Object Identifier (DOI)

  • 10.1152/ajpendo.00464.2009

Language

  • eng