2-Deoxy-D-glucose uptake by lung slices from fed and fasted rats

We studied the uptake and phosphorylation of 2-deoxy-D-[1-14C]glucose (2-[14C]DG) by lung slices from fed and fasted rats to obtain information on the effect of starvation on surgar transport by the lung. We found that 2-[14C]DG is taken up and phosphorylated by the lung, but that, as in other tissues it is not metabolized beyond the phosphorylation step. The accumulation of 2-[14C]DG as free 2-DG does not require energy, fails to show saturation in the range studied (5-100 mM), and is not inhibited by exogenous glucose. The phosphorylation of 2-DG by the lung is energy dependent, saturable, and competitively inhibited by exogenous glucose. Fasting does not interfere with the intracellular accumulation of unphosphorylated 2-DG but causes about a 40% decrease in the accumulation of phosphorylated 2-DG. We conclude that membrane transport does not limit uptake of 2-DG; fasting decreases the phosphorylation of 2-DG.