Hexose transport by brain slices: further studies on energy dependence.
We studied the uptake of [3H]2-deoxyglucose [( 3H]2DG) by slices of rat cerebral cortex in vitro as a model of glucose transport by brain. Slices were incubated with [3H]2DG, or with L-[3H]glucose as a marker for diffusion; the difference between [3H]2DG uptake and L-[3H]glucose uptake was defined as net [3H]2DG transport. Net [3H]2DG transport was a function of incubation temperature, with an estimated temperature coefficient of 1.87 from 15 degrees C to 25 degrees C. The net uptake of [3H]2DG was not inhibited by phlorizin or phloretin in concentrations well above the reported Ki of these inhibitors for hexose uptake in other systems. To examine the hypothesis that [3H]2DG transport by brain slices is dependent on mitochondrial energy, we studied net [3H]2DG uptake by slices which had been preincubated in media designed to alter intracellular ATP stores. The transport process was very sensitive to inhibition by DNP, but the correlation between [3H]2DG transport and ATP levels was unclear. In contrast to our published hypothesis that the transport process required mitochondrial energy, these data indicate that dependence on energy is not absolute.
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D001693:Biological Transport, Active; D002540:Cerebral Cortex / Q000378:metabolism*; D003837:Deoxy Sugars / Q000378:metabolism*; D003847:Deoxyglucose / Q000378:metabolism*; D004734:Energy Metabolism; D005947:Glucose / Q000378:metabolism*; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013696:Temperature; D014316:Tritium
D003837:Deoxy Sugars; D014316:Tritium; D000255:Adenosine Triphosphate; D003847:Deoxyglucose; D005947:Glucose