Exercise training improves muscle insulin resistance but not insulin receptor signaling in obese Zucker rats

Abstract

John L. Ivy. Exercise training improves muscle insulin resistance but not insulin receptor signaling in obese Zucker rats. J Appl Physiol 92: 736–744, 2002; 10.1152/japplphysiol. 00784.2001.—Exercise training improves skeletal muscle in-sulin sensitivity in the obese Zucker rat. The purpose of this study was to investigate whether the improvement in insulin action in response to exercise training is associated with enhanced insulin receptor signaling. Obese Zucker rats were trained for 7 wk and studied by using the hindlimb-perfusion technique 24 h, 96 h, or 7 days after their last exercise training bout. Insulin-stimulated glucose uptake (traced with 2-deoxyglucose) was significantly reduced in untrained obese Zucker rats compared with lean controls (2.2 0.17 vs. 5.4 0.46 mol g1 h1). Glucose uptake was normalized 24 h after the last exercise bout (4.9 0.41 mol g1 h1