Diabetes 54:2447-2452, 2005 © 2005 by the American Diabetes Association, Inc. Rosiglitazone Reduces Glucose-Stimulated Insulin Secretion Rate and Increases Insulin Clearance in Nondiabetic, Insulin-Resistant Individuals
1 Department of Medicine, Stanford University School of Medicine, Stanford, California
Compensatory hyperinsulinemia permitting insulin-resistant individuals to maintain normal glucose tolerance is associated with a left shift in the glucose-stimulated insulin secretion rate (GS-ISR) dose-response curve and decrease in the insulin metabolic clearance rate (I-MCR). To see whether these changes would reverse with improvement in insulin sensitivity, 14 nondiabetic insulin-resistant subjects received rosiglitazone for 12 weeks (4 mg daily for 4 weeks and then 8 mg daily for 8 weeks). Insulin-mediated glucose uptake was quantified by measuring the steady-state plasma glucose concentration during the insulin suppression test. GS-ISR and I-MCR were determined during a 240-min graded intravenous glucose infusion. I-MCR was also calculated during the insulin suppression test. After rosiglitazone treatment, insulin sensitivity improved with significant fall in steady-state plasma glucose (means ± SE from 13.5 ± 0.62 to 9.8 ± 1.02 mmol/l, P < 0.001). In response, the integrated GS-ISR decreased by 21% (P < 0.001), with a right shift in the dose-response curve. Calculated I-MCR increased by 34% (P = 0.008) during the insulin suppression test and by 21% (P = 0.03) during the graded glucose infusion. In conclusion, enhanced insulin sensitivity in rosiglitazone-treated nondiabetic insulin-resistant individuals was associated with a shift to the right in the GS-ISR dose-response curve and an increase in I-MCR.
Address correspondence and reprint requests to Gerald M. Reaven, MD, Division of Cardiovascular Medicine, Falk Cardiovascular Research Center, Stanford Medical Center, 300 Pasteur Dr., Stanford, CA 94305-5406. E-mail: greaven{at}cvmed.stanford.edu
Abbreviations: AUC, area under the curve; FFA, free fatty acid; GS-ISR, glucose-stimulated insulin secretion rate; I-MCR, insulin metabolic clearance rate; SSPG, steady-state plasma glucose
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