In preparation for PET imaging of ischemic myocardial regions, the uptake of 218F-fluoro-2-deoxy-D-glucose (FDG) in the isolated perfused rat heart was studied under normoxic and hypoxic conditions. With this model we were able to demonstrate an about 2.5 fold higher uptake of FDG in hypoxia compared with the normoxic heart. FDG uptake is considered as a measure for glucose utilization; hence the higher uptake in hypoxia points to an increased glucose metabolism. This was to be expected because in hypoxia the main energy source of the normal well-oxygenated myocardium, the free fatty acids, cannot be oxidized, and the myocardium is forced to utilize glucose via the glycolytic pathway.