Coupling between the intracellular pH and the active transport of sodium in an epithelial cell line from Xenopus laevis

Comp Biochem Physiol Comp Physiol. 1992 May;102(1):7-14. doi: 10.1016/0300-9629(92)90003-9.


1. The relationship between the rate of active Na+ transport and intracellular pH (pHi, measured as the BCECF fluorescence) was studied in A6 monolayers in the presence of CO2. The total buffering power (beta total) and its components (beta i and beta CO2) were assessed at various pHi. 2. The activity of Na+/H+ and Cl-/HCO3- exchangers were expressed in A6 cells; both antiports were found to participate in pHi homeostasis under standard conditions. 3. Alterations in the rate of Na+ transport induced variations in pHi. 4. Na+ transport rate was a hyperbolic function of external Na+ concentration. The curve was shifted by changing pHi: a mixed inhibition of Na+ transport by pHi was found. 5. The pHi appears as a possible mediator coupling the rate of Na+ transport across the apical and the basolateral membrane in tight epithelia.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amiloride / pharmacology
  • Animals
  • Biological Transport, Active / drug effects
  • Buffers
  • Cell Line
  • Epithelium / metabolism
  • Hydrogen-Ion Concentration
  • Intracellular Fluid / drug effects
  • Intracellular Fluid / metabolism
  • Sodium / metabolism*
  • Xenopus laevis


  • Buffers
  • Amiloride
  • Sodium