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Journal of Diabetes Research
Volume 2014, Article ID 524517, 10 pages
http://dx.doi.org/10.1155/2014/524517
Research Article

The GLP-1 Analogue Exenatide Improves Hepatic and Muscle Insulin Sensitivity in Diabetic Rats: Tracer Studies in the Basal State and during Hyperinsulinemic-Euglycemic Clamp

Institute and Department of Endocrinology and Metabolism, Shanghai Ninth People’s Hospital Affiliated Shanghai Jiaotong University School of Medicine, Shanghai 200011, China

Received 14 August 2014; Revised 17 October 2014; Accepted 18 October 2014; Published 16 November 2014

Academic Editor: Bernard Portha

Copyright © 2014 Hui Wu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Objective. Glucagon-like peptide-1 (GLP-1) analogues (e.g., exenatide) increase insulin secretion in diabetes but less is known about their effects on glucose production or insulin-stimulated glucose uptake in peripheral tissues. Methods. Four groups of Sprague-Dawley rats were studied: nondiabetic (control, C); nondiabetic + exenatide (C + E); diabetic (D); diabetic + exenatide (D + E) with diabetes induced by streptozotocin and high fat diet. Infusion of 3-3H-glucose and U-13C-glycerol was used to measure basal rates of appearance () of glucose and glycerol and gluconeogenesis from glycerol (GNG). During hyperinsulinemic-euglycemic clamp, glucose uptake into gastrocnemius muscles was measured with 2-deoxy-D-14C-glucose. Results. In the diabetic rats, exenatide reduced the basal of glucose () and glycerol () and GNG (). During the clamp, of glucose was also reduced, whereas the rate of disappearance of glucose increased and there was increased glucose uptake into muscle () during the clamp. In the nondiabetic rats, exenatide had no effect. Conclusion. In addition to its known effects on insulin secretion, administration of the GLP-1 analogue, exenatide, is associated with increased inhibition of gluconeogenesis and improved glucose uptake into muscle in diabetic rats, implying improved hepatic and peripheral insulin sensitivity.