| Method |
Glucose uptake was determined by incubating cells with D-[U-14C]glucose (GE Healthcare, Buckinghamshire, United Kingdom). Aliquots of resuspended cells were sequentially removed from ice and held in a water bath at 37°C for 10 min. A 500-µl volume of the cell suspension was added to 50 µl of a 37°C glucose solution, and then the sample was immediately vortexed and returned to the 37°C bath for an incubation time of 5 min unless specified otherwise. For standard assays, the final concentrations of glucose were 1 mM and 0.2 µCi/ml. |