Summary
The properties of two sodium-dependentd-glucose transporters previously identified in renal proximal tubule brush border membrane (BBM) vesicles are studied. The low-affinity system, found in BBM vesicles from the outer cortex (early proximal tubule), is shown to be associated with the high-affinity phlorizin binding site typically found in renal BBM preparations. The high-affinity system, found in BBM vesicles from the outer medulla (late proximal tubule), is almost two orders of magnitude less sensitive to inhibition by phlorizin and is apparently not associated with high-affinity phlorizin binding. The sodium/g;ucose stoichiometry of the outer medullary transporter is found to be 2∶1 by two independent methods. Previous measurements have established that the stoichiometry of the outer cortical system is 1∶1. It is suggested that this arrangement of transporters in series along the proximal tubule enables the kidney to reabsorb glucose from the urine in an energy-efficient fashion. The bulk of the glucose load is reabsorbed early in the proximal tubule at an energetic cost of one Na+ per glucose molecule. Then in the late proximal tubule a larger coupling ratio and hence a larger driving force is employed to reabsorb the last traces of glucose from the urine.
Similar content being viewed by others
References
Aronson, P.S. 1978. Energy dependence of phlorizin binding to isolated renal microvillus membranes.J. Membrane Biol. 42:81–98
Aronson, P.S. 1981. Identifying secondary active transport in epithelia.Am. J. Physiol. 240:F1-F11
Aronson, P.S., Sacktor, B. 1975. The Na gradient dependent transport ofd-glucose in renal brush border membranes.J. Biol. Chem. 250:6032–6039
Barfuss, D.W., Schafer, J.A. 1981. Differences in active and passive glucose transport along the proximal nephron.Am. J. Physiol. 241:F322-F332
Bode, F., Baumann, K., Diedrich, D.F. 1972. Inhibition of phlorizin binding to isolated kidney brush border membranes by phlorizin-like compounds.Biochim. Biophys. Acta 290:134–149
Booth, A.G., Kenny, A.J. 1976. A morphometric and biochemical investigation of the vesiculation of kidney microvilli.J. Cell Sci. 21:449
Chesney, R., Sacktor, B., Kleinzeller, A. 1974. The binding of phlorizin to isolated luminal membrane of the renal proximal tubule.Biochim. Biophys. Acta 332:263–277
Crane, R.K. 1977. The gradient hypothesis and other models of carrier mediated active transport.Rev. Physiol. Biochem. Pharmacol. 78:99–159
Frasch, W., Frohnert, P.P., Bode, F., Baumann, K., Kinne, R. 1970. Competitive inhibition of phlorizin binding byd-glucose and the influence of sodium: A study on isolated brush border membrane of rat kidney.Pfluegers Arch. 320:265–284
Glossmann, H., Neville, D.M., Jr. 1972. Phlorizin receptors in isolated kidney brush border membranes.J. Biol. Chem. 247:7779–7789
Grinstein, S., Turner, R.J., Silverman, M., Rothstein, A. 1980. Inorganic anion transport in kidney and intestinal brush border and basolateral membranes.Am. J. Physiol. 238:F452
Haase, W., Schafer, A., Murer, H., Kinne, R. 1978. Studies on the orientation of brush border membrane vesicles.Biochem. J. 172:57
Lin, J.T., Da Cruz, M.E.M., Riedel, S., Kinne, R. 1981. Partial purification of hog kidney sodiumd-glucose cotransport system by affinity chromatography on a phlorizin polymer.Biochim. Biophys. Acta 640:43–54
Segel, I.H. 1975. Enzyme Kinetics. John Wiley and Sons, New York
Silverman, M. 1976. Glucose transport in the kidney.Biochim. Biophys. Acta 457:303–351
Silverman, M., Black, J. 1975. High affinity phlorizin receptor sites and their relation to the glucose transport mechanisms in the proximal tubule of dog kidney.Biochim. Biophys. Acta 394:10–30
Turner, R.J. 1981. Kinetic analysis of a family of cotransport models.Biochim. Biophys. Acta 649:269–280
Turner, R.J., Moran, A. 1982. Heterogeneity of sodium dependentd-glucose transport sites along the proximal tubule: Evidence from vesicle studies.Am. J. Physiol. 242:F406-F414
Turner, R.J., Moran, A. 1982. Stoichiometric studies of the renal outer cortical brush border membraned-glucose transporter.J. Membrane Biol. 67:73–80
Turner, R.J., Silverman, M. 1977. Sugar uptake into normal human renal brush border vesicles.Proc. Natl. Acad. Sci. USA 75:2825–2829
Turner, R.J., Silverman, M. 1978. Sugar uptake into brush border vesicles from dog kidney. I. Specificity.Biochim. Biophys. Acta 507:305–321
Turner, R.J., Silverman, M. 1978. Sugar uptake into brush border vesicles from dog kidney. II. Kinetics.Biochim. Biophys. Acta 511:470–486
Turner, R.J., Silverman, M. 1981. Interaction of phlorizin and sodium with the renal brush border membraned-glucose transporter: Stoichiometry and order of binding.J. Membrane Biol. 58:43–55
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Turner, R.J., Moran, A. Further studies of proximal tubular brush border membraned-glucose transport heterogeneity. J. Membrain Biol. 70, 37–45 (1982). https://doi.org/10.1007/BF01871587
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF01871587