Uptake of 18F-Labeled 6-Fluoro-6-Deoxy- D-Glucose by Skeletal Muscle Is Responsive to Insulin Stimulation

We are developing amethodology for the noninvasive imaging of glucose transport in vivo with PET and 18F-labeled 6-fluoro-6-deoxy-D-glucose (18F-6FDG), a tracer that is transported but not phosphorylated. To validate the method, we evaluated the biodistribution of 18F-6FDG to test whether it is consistent with the known properties of glucose transport, particularly with regard to insulin stimulation of glucose transport.Methods: Un-der glucose clamp conditions, rats were imaged at the baseline and under conditions of hyperinsulinemia. Results: The images showed that the radioactivity concentration in skeletal muscle was higher in the presence of insulin than at the baseline. We also found evidence that the metabolism of 18F-6FDG was neg-ligible in several tissues. Conclusion: 18F-6FDG is a valid tracer that can be used in in vivo transport studies. PET studies per-formed under glucose clamp conditions demonstrated that the uptake of nonphosphorylated glucose transport tracer 18F-6FDG is sensitive to insulin stimulation