T Torizuka1, S J Fisher, R L Wahl. 1. Department of Internal Medicine, University of Michigan Medical Center, Ann Arbor 48109-0028, USA.
Abstract
PURPOSE: To determine, in an animal study, whether insulin-induced hypoglycemia enhances tumor uptake of 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) in vivo. MATERIALS AND METHODS: Rat mammary tumors were established subcutaneously in Lewis rats. When the tumor was 1-2 cm in diameter, rats were fasted overnight and divided into two groups: control rats (n = 5) that received saline and hypoglycemic rats (n = 5) that received insulin. After 30 minutes, FDG (200 microCi [7.4 MBq]) was given intravenously. One hour after FDG injection (ie, at sacrifice), plasma glucose and insulin levels were measured and F-18 activity in tumor and normal tissues was determined. RESULTS: Mean glucose level was 32.8 mg/dL (1.8 mmol/L) and mean insulin level was 2,831.1 microU/mL (20,315 pmol/L) in the hypoglycemic animals. As compared with the control value, mean FDG uptake in tumor (percentage of injected dose [per gram of tissue] per kilogram of animal weight) significantly decreased with hypoglycemia (0.117 vs 0.331, P = .0001). Mean FDG uptake in the heart and muscle was 9.75 and 5.18 times higher, respectively, in the hypoglycemic rats (P = .0001). Thus, the tumor/muscle uptake ratio was significantly reduced with hypoglycemia (2.15 vs 31.62, P = .0002). CONCLUSION: Tumor targeting with FDG is impaired, not enhanced, by insulin-induced hypoglycemia.
PURPOSE: To determine, in an animal study, whether insulin-induced hypoglycemia enhances tumor uptake of 2-[fluorine-18]fluoro-2-deoxy-D-glucose (FDG) in vivo. MATERIALS AND METHODS:Rat mammary tumors were established subcutaneously in Lewis rats. When the tumor was 1-2 cm in diameter, rats were fasted overnight and divided into two groups: control rats (n = 5) that received saline and hypoglycemic rats (n = 5) that received insulin. After 30 minutes, FDG (200 microCi [7.4 MBq]) was given intravenously. One hour after FDG injection (ie, at sacrifice), plasma glucose and insulin levels were measured and F-18 activity in tumor and normal tissues was determined. RESULTS: Mean glucose level was 32.8 mg/dL (1.8 mmol/L) and mean insulin level was 2,831.1 microU/mL (20,315 pmol/L) in the hypoglycemic animals. As compared with the control value, mean FDG uptake in tumor (percentage of injected dose [per gram of tissue] per kilogram of animal weight) significantly decreased with hypoglycemia (0.117 vs 0.331, P = .0001). Mean FDG uptake in the heart and muscle was 9.75 and 5.18 times higher, respectively, in the hypoglycemic rats (P = .0001). Thus, the tumor/muscle uptake ratio was significantly reduced with hypoglycemia (2.15 vs 31.62, P = .0002). CONCLUSION:Tumor targeting with FDG is impaired, not enhanced, by insulin-induced hypoglycemia.
Authors: Emilio Bombardieri; Cumali Aktolun; Richard P Baum; Angelika Bishof-Delaloye; John Buscombe; Jean François Chatal; Lorenzo Maffioli; Roy Moncayo; Luc Mortelmans; Sven N Reske Journal: Eur J Nucl Med Mol Imaging Date: 2003-12 Impact factor: 9.236