2-Deoxy-D-glucose transport in dog kidney

Abstract

Osmotically active brush border membrane (BBM) and antiluminal membrane (ALM) vesicles prepared from dog kidney cortex were used to investigate transport of 2-deoxy-D-glucose (2DG). A parallel in vivo study was carried out using the pulse-injection multiple indicator-dilution technique. Single-pass indicator-dilution experiments demonstrate both luminal and antiluminal interactions for 2DG. The antiluminal interaction is blocked by large systemic doses of phlorizin (100-200 mg/kg). With plasma glucose concentration in the range of 4-5 mM fractional luminal extraction of 2-[14C]DG relative to simultaneously filtered creatinine is 25 +/- 2%. This luminal extraction can be inhibited by raising plasma glucose concentration to approximately 30 mM and by administration of low systemic doses of phlorizin (6-8 mg/Kg). 2DG uptake into BBM vesicles equilibrates into the same intravesicular volume as D-glucose. A definite Na+ component of 2DG uptake can be defined which is more sensitive to inhibition by phlorizin than by phloretin and is also inhibited by D-glucose and alpha-methyl-D-glucoside but not by L-glucose. But compared with D-glucose, the Na+-dependent BBM uptake of 2DG is greatly reduced. 2DG uptake into ALM vesicles is independent of Na+, is more sensitive to inhibition by phloretin than by phlorizin, and is also blocked by cytochalasin B but not by alpha-methyl-D-glucoside. Influx of 2-[14C] DG into ALM vesicles is increased by preloading with unlabeled D-glucose. Conversely influx of D[14C]glucose into ALM vesicles is accelerated by preloading with unlabeled 2DG. ALM influx of radiolabeled 2DG is accelerated by D-glucose, 3-O-methyl-D-glucose, D-galactose, and unlabeled 2DG but not by alpha-methyl-D-glucoside. The specificity of inhibition and countertransport results from in vivo and in vitro experiments are consistent with the proposal that 2DG shares a common carrier mechanism with D-glucose at each of the opposing membrane surfaces.