18F-FDG assessment of glucose disposal and production rates during fasting and insulin stimulation: a validation study

The glucose analog 18F-FDG is commonly used to quantify regional glucose uptake in vivo. The aim of this study was to test whether the analysis of plasma 18F-FDG kinetics could be used to estimate endogenous glucose production (EGP) and the total rate of appearance (Ra), total rate of disappearance (Rd), and the metabolic clearance rate (MCR) of glucose. Methods: Fourteen pigs were coinjected with 18F-FDG and 6,6-2H-glucose (2H-G) during fasting (n = 6) and during physiologic (1.0 mU·kg-1·min-1, n = 4) and supraphysiologic (5.0 mU·kg-1·min-1, n = 4) euglycemic hyperinsulinemia. Arterial plasma was sampled for 180 min to quantify the parameters for the 2 tracers. Results: Fasting Rd2H-G and RdFDG were 12.3 ± 2.1 and 13.3 ± 1.3 µmol·kg-1·min-1 (difference not statistically significant [NS]). M values were more than doubled between the 2 clamp studies (P 0.0001). Rd2H-G and RdFDG were dose-dependently higher during the hyperinsulinemic state (19.8 ± 3.7 vs. 18.9 ± 1.1 and 31.4 ± 4.1 vs. 31.9 ± 2.3 in 1.0 and 5.0 mU·kg-1·min-1 studies, respectively; difference between tracers NS) than during the fasting state, with a parallel suppression of EGP2H-G and EGPFDG. Parameters estimated by 18F-FDG and 2H-G were equivalent in all groups; their agreement was confirmed by Bland-Altman examination. Total RdFDG correlated with Rd2H-G (r