Influence of dietary state and insulin on myocardial, skeletal muscle and brain 18F-fluorodeoxyglucose kinetics in miceReport as inadecuate




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EJNMMI Research

, 1:8

First Online: 06 July 2011Received: 13 March 2011Accepted: 06 July 2011

Abstract

BackgroundWe evaluated the effect of insulin stimulation and dietary changes on myocardial, skeletal muscle and brain F-fluorodeoxyglucose FDG kinetics and uptake in vivo in intact mice.

MethodsMice were anesthetized with isoflurane and imaged under different conditions: non-fasted n = 7; -controls-, non-fasted with insulin 2 IU-kg body weight injected subcutaneously immediately prior to FDG n = 6, fasted n = 5, and fasted with insulin injection n = 5. A 60-min small-animal PET with serial blood sampling and kinetic modeling was performed.

ResultsWe found comparable FDG standardized uptake values SUVs in myocardium in the non-fasted controls and non-fasted-insulin injected group SUV 45-60 min, 9.58 ± 1.62 vs. 9.98 ± 2.44; p = 0.74, a lower myocardial SUV was noted in the fasted group 3.48 ± 1.73; p < 0.001. In contrast, the FDG uptake rate constant Ki for myocardium increased significantly by 47% in non-fasted mice by insulin 13.4 ± 3.9 ml-min-100 g vs. 19.8 ± 3.3 ml-min-100 g; p = 0.030; in fasted mice, a lower myocardial Ki as compared to controls was observed 3.3 ± 1.9 ml-min-100 g; p < 0.001. Skeletal muscle SUVs and Ki values were increased by insulin independent of dietary state, whereas in the brain, those parameters were not influenced by fasting or administration of insulin. Fasting led to a reduction in glucose metabolic rate in the myocardium 19.41 ± 5.39 vs. 3.26 ± 1.97 mg-min-100 g; p < 0.001, the skeletal muscle 1.06 ± 0.34 vs. 0.34 ± 0.08 mg-min-100 g; p = 0.001 but not the brain 3.21 ± 0.53 vs. 2.85 ± 0.25 mg-min-100 g; p = 0.19.

ConclusionsChanges in organ SUVs, uptake rate constants and metabolic rates induced by fasting and insulin administration as observed in intact mice by small-animal PET imaging are consistent with those observed in isolated heart-muscle preparations and, more importantly, in vivo studies in larger animals and in humans. When assessing the effect of insulin on the myocardial glucose metabolism of non-fasted mice, it is not sufficient to just calculate the SUV - dynamic imaging with kinetic modeling is necessary.

Electronic supplementary materialThe online version of this article doi:10.1186-2191-219X-1-8 contains supplementary material, which is available to authorized users.

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Author: Michael C Kreissl - David B Stout - Koon-Pong Wong - Hsiao-Ming Wu - Evren Caglayan - Waldemar Ladno - Xiaoli Zhang - Joh

Source: https://link.springer.com/







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