Determination of Glucose Utilization Rates in Cultured Astrocytes and Neurons with [C]deoxyglucose: Progress, Pitfalls, and Discovery of Intracellular Glucose Compartmentation.

2-Deoxy-D-[C]glucose ([C]DG) is commonly used to determine local glucose utilization rates (CMR) in living brain and to estimate CMR in cultured brain cells as rates of [C]DG phosphorylation. Phosphorylation rates of [C]DG and its metabolizable fluorescent analog, 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)amino)-2-deoxyglucose (2-NBDG), however, do not take into account differences in the kinetics of transport and metabolism of [C]DG or 2-NBDG and glucose in neuronal and astrocytic cells in cultures or in single cells in brain tissue, and conclusions drawn from these data may, therefore, not be correct. As a first step toward the goal of quantitative determination of CMR in astrocytes and neurons in cultures, the steady-state intracellular-to-extracellular concentration ratios (distribution spaces) for glucose and [C]DG were determined in cultured striatal neurons and astrocytes as functions of extracellular glucose concentration.