Identification of proximal tubular transport functions in the established kidney cell line, OK

Biochim Biophys Acta. 1987 Aug 20;902(2):269-77. doi: 10.1016/0005-2736(87)90305-1.


OK cells, derived from an American opossum kidney, were analyzed for proximal tubular transport functions. In monolayers, L-glutamate, L-proline, L-alanine, and alpha-methyl-glucopyranoside (alpha-methyl D-glucoside) were accumulated through Na+-dependent and Na+-independent transport pathways. D-Glucose and inorganic sulfate were accumulated equally well in the presence or absence of Na+. Influx of inorganic phosphate was only observed in the presence of Na+. Na+/alpha-methyl D-glucoside uptake was preferentially inhibited by phlorizin and D-glucose uptake by cytochalasin B. An amiloride-sensitive Na+-transport was also identified. In isolated apical vesicles (enriched 8-fold in gamma-glutamyltransferase), L-glutamate, L-proline, L-alanine, alpha-methyl D-glucoside and inorganic phosphate transport were stimulated by an inwardly directed Na+-gradient as compared to an inwardly directed K+-gradient. L-Glutamate transport required additionally intravesicular K+. D-Glucose transport was similar in the presence of a Na+- and a K+-gradient. Na+/alpha-methyl D-glucoside uptake was inhibited by phlorizin whereas cytochalasin B had no effect on Na+/D-glucose transport. An amiloride-sensitive Na+/H+ exchange mechanism was also found in the apical vesicle preparation. It is concluded that the apical membrane of OK cells contains Na+-coupled transport systems for amino acids, hexoses, protons and inorganic phosphate. D-Glucose appears a poor substrate for the Na+/hexose transport system.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acids / metabolism
  • Animals
  • Biological Transport
  • Cell Line
  • Glucose / metabolism
  • Hydrogen-Ion Concentration
  • Kidney Tubules, Proximal / metabolism*
  • Opossums
  • Phosphates / metabolism
  • Sodium / metabolism
  • Sodium / pharmacology


  • Amino Acids
  • Phosphates
  • Sodium
  • Glucose