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Updated: Dec 2, 2025

Hyperinsulinemic-euglycemic Clamps in Conscious, Unrestrained Mice
Published on: November 16, 2011
Pancreatic GLP-1r binding potential is reduced in insulin-resistant pigs
Charles-Henri Malbert1, Alain Chauvin2, Michael Horowitz3
1Aniscan Unit, Department of Human Nutrition, INRAE, Saint-Gilles, France charles-henri.malbert@inrae.fr.
Introduction:
The insulinotropic capacity of exogenous glucagon like peptide-1 (GLP-1) is reduced in type 2 diabetes and the insulin-resistant obese. We have tested the hypothesis that this response is the consequence of a reduced pancreatic GLP-1 receptor (GLP-1r) density in insulin-resistant obese animals.
Research Design And Methods:
GLP-1r density was measured in lean and insulin-resistant adult miniature pigs after the administration of a 68Ga-labeled GLP-1r agonist. The effect of hyperinsulinemia on GLP-1r was assessed using sequential positron emission tomography (PET), both in the fasted state and during a clamp. The impact of tissue perfusion, which could account for changes in GLP-1r agonist uptake, was also investigated using 68Ga-DOTA imaging.
Results:
GLP-1r binding potential in the obese pancreas was reduced by 75% compared with lean animals. Similar reductions were evident for fat tissue, but not for the duodenum. In the lean group, induced hyperinsulinemia reduced pancreatic GLP-1r density to a level comparable with that of the obese group. The reduction in blood to tissue transfer of the GLP-1r ligand paralleled that of tissue perfusion estimated using 68Ga-DOTA.
Conclusions:
These observations establish that a reduction in abdominal tissue perfusion and a lower GLP-1r density account for the diminished insulinotropic effect of GLP-1 agonists in type 2 diabetes.
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