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

We are developing a methodology for the noninvasive imaging of glucose transport in vivo with PET and F-18-labeled 6-fluoro-6-deoxy- D-glucose (F-18-6FDG), a tracer that is transported but not phosphorylated. To validate the method, we evaluated the biodistribution of F-18-6FDG to test whether it is consistent with the known properties of glucose transport, particularly with regard to insulin stimulation of glucose transport. Methods: Under 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 F-18-6FDG was negligible in several tissues. Conclusion: F-18-6FDG is a valid tracer that can be used in in vivo transport studies. PET studies performed under glucose clamp conditions demonstrated that the uptake of nonphosphorylated glucose transport tracer F-18-6FDG is sensitive to insulin stimulation.