Ulster University Logo

Effects of gastric inhibitory polypeptide (GIP) and related analogues on glucagon release at normo- and hyperglycaemia in Wistar rats and isolated islets

Cassidy, Roslyn S., Irwin, Nigel and Flatt, Peter (2008) Effects of gastric inhibitory polypeptide (GIP) and related analogues on glucagon release at normo- and hyperglycaemia in Wistar rats and isolated islets. BIOLOGICAL CHEMISTRY, 389 (2). pp. 189-193. [Journal article]

Full text not available from this repository.

DOI: 10.1515/BC.2008.019

Abstract

Glucose-dependent insulinotropic polypeptide (GIP) is an incretin hormone secreted by endocrine K-cells in response to nutrient absorption. This study has utilised numerous well-characterised dipeptidyl peptidase IV-resistant GIP analogues to evaluate the glucagonotropic actions of GIP in Wistar rats and isolated rat islets. Intraperitoneal administration of GIP analogues (25 nmol/kg body weight) in combination with glucose had no effect on circulating glucagon concentrations compared to controls in Wistar rats. However, plasma glucose concentrations were significantly (p<0.05 to p<0.001) lowered by the GIP-receptor agonists, N-AcGIP, GIP(Lys(37)) PAL and N-AcGIP(Lys(37))PAL. The GIP antagonist, (Pro(3))GIP, caused a significant (p<0.05) reduction in glucagon levels following concurrent administration with saline in Wistar rats. In isolated rat islets native GIP induced a significant (p<0.01) enhancement of glucagon release at basal glucose concentrations, which was completely annulled by (Pro(3))GIP. Furthermore, glucagon release in the presence of GLP-1, GIP(Lys(37))PAL, N-AcGIP(Lys(37)) PAL and (Pro(3))GIP was significantly (p<0.05 to p<0.001) decreased compared to native GIP in isolated rat islets. These data indicate a modest effect of GIP on glucagon secretion from isolated rat islets, which was not observed in vivo. However, the GIP agonists N-AcGIP, GIP(Lys(37))PAL and N-AcGIP(Lys(37))PAL had no effect on glucagon release demonstrating an improved therapeutic potential for the treatment of type 2 diabetes.

Item Type:Journal article
Faculties and Schools:Faculty of Life and Health Sciences > School of Biomedical Sciences
Faculty of Life and Health Sciences > School of Pharmacy and Pharmaceutical Science
Faculty of Life and Health Sciences
Research Institutes and Groups:Biomedical Sciences Research Institute
Biomedical Sciences Research Institute > Diabetes
ID Code:2923
Deposited By: Professor Peter Flatt
Deposited On:17 Dec 2009 10:22
Last Modified:19 Nov 2012 15:54

Repository Staff Only: item control page