EVIDENCE THAT MODULATION OF GLUCOSE-TRANSPORTER INTRINSIC ACTIVITY ISTHE MECHANISM INVOLVED IN THE ALLOSE-MEDIATED DEPRESSION OF HEXOSE-TRANSPORT IN MAMMALIAN-CELLS

In serum starved V79 Chinese hamster lung fibroblast cells, replacemen t of D-glucose with D-allose resulted in a significant 38 +/- 18% (P < 0.05) reduction of 2-deoxy-D-glucose (2-DC) transport. Similarly, in a respiration-deficient mutant cell line (V79-G14), wh ich has elevate d 2-DG transport activity, D-allose reduced 2-DC transport by 59 +/- 1 8% (P < 0.05). [H-3] D-allose uptake by V79 cells occurred slowly and was not inhibited by cytochalasin 8, suggesting diffusion as the mode of D-allose entry. Western blot analysis using a rabbit polyclonal ant ibody to the human erythrocyte glucose transporter (GT) demonstrated t hat, in both cell lines, GT content and GT subcellular distribution we re not significantly different in D-glucose vs. D-allose-treated cells . delta-Antibody, which has been shown to bind to exofacial epitopes o f the GT (Harrison et al., 1990, J. Biol. Chem., 265:5793-5807), did n ot demonstrate any differences in surface binding to D-glucose vs. D-a llose-treated intact V79 cells. D-allose treatment of 3T3 fibroblasts resulted in a similar decrease (72%) of 2-DC transport, however D-allo se had no apparent effect on basal sugar transport in 3T3 adipocytes. These results suggest that D-allose reduces sugar transport through a modulation of the intrinsic activity of the CT, and that D-allose may act in a tissue-specific manner. (C) 1994 Wiley-Liss, Inc.