Evidence that modulation of glucose transporter intrinsic activity is the mechanism involved in the allose‐mediated depression of hexose transport in mammalian cells

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Abstract
In serum starved V79 Chinese hamster lung fibroblast cells, replacement of D‐glucose with D‐allose resulted in a significant 38 ± 18% (P < 0.05) reduction of 2‐deoxy‐D‐glucose (2‐DG) transport. Similarly, in a respiration‐deficient mutant cell line (V79‐G14), which has elevated 2‐DG transport activity, D‐allose reduced 2‐DG transport by 59 ± 18% (P < 0.05). [3H]D‐allose uptake by V79 cells occurred slowly and was not inhibited by cytochalasin B, suggesting diffusion as the mode of D‐allose entry. Western blot analysis using a rabbit polyclonal antibody to the human erythrocyte glucose transporter (GT) demonstrated that, in both cell lines, GT content and GT subcellular distribution were not significantly different in D‐glucose vs. D‐allose‐treated cells. δ‐Antibody, which has been shown to bind to exofacial epitopes of the GT (Harrison et al., 1990, J. Biol. Chem., 265:5793‐‐5801), did not demonstrate any differences in surface binding to D‐glucose vs. D‐allose‐treated intact V79 cells. D‐allose treatment of 3T3 fibroblasts resulted in a similar decrease (72%) of 2‐DG transport, however D‐allose 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 GT, and that D‐allose may act in a tissue‐specific manner.