Low-NaCl diet increases H-K-ATPase in intercalated cells from rat cortical collecting duct

Am J Physiol. 1998 Jul;275(1):F94-102. doi: 10.1152/ajprenal.1998.275.1.F94.

Abstract

Extracellular K+-dependent H+ extrusion after an acute acid load, an index of H/K exchange, was monitored in intercalated cells (ICs) from rat cortical collecting tubule (CCT) using ratiometric fluorescence imaging of the intracellular pH (pHi) indicator, 2',7'-bis(2-carboxyethyl)-5(6)-carboxyfluorescein (BCECF). The hypothesis tested was that 12- to 14-day NaCl deprivation increases H-K-ATPase in rat ICs. The rate of H/K exchange in the low-NaCl ICs was double that of controls. In control ICs, H/K exchange was inhibited by Sch-28080 (10 microM). In the low-NaCl ICs, it was partially blocked by Sch-28080 or ouabain (1 mM). Simultaneous addition of both inhibitors abolished K-dependent pHi recovery. The induced H/K exchange observed with NaCl restriction was not due to elevated plasma aldosterone as evidenced by experiments on ICs from rats implanted with osmotic minipumps administering aldosterone such that plasma levels were comparable to those of NaCl-deficient rats. The results suggest that NaCl deficiency induces two isoforms of H-K-ATPase in ICs and that this effect is not mediated by elevated plasma aldosterone.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Aldosterone / blood
  • Aldosterone / pharmacology
  • Animals
  • Anti-Bacterial Agents / pharmacology
  • Diet, Sodium-Restricted*
  • Electrolytes / blood
  • Electrolytes / urine
  • Enzyme Induction
  • Enzyme Inhibitors / pharmacology
  • Female
  • H(+)-K(+)-Exchanging ATPase / biosynthesis*
  • Hydrogen-Ion Concentration
  • Imidazoles / pharmacology
  • Kidney Cortex / cytology*
  • Kidney Cortex / enzymology*
  • Kidney Cortex / physiology
  • Kidney Tubules, Collecting / cytology*
  • Kidney Tubules, Collecting / enzymology*
  • Kidney Tubules, Collecting / physiology
  • Kinetics
  • Macrolides*
  • Male
  • Ouabain / pharmacology
  • Proton Pump Inhibitors
  • Rats
  • Rats, Sprague-Dawley
  • Reference Values
  • Time Factors

Substances

  • Anti-Bacterial Agents
  • Electrolytes
  • Enzyme Inhibitors
  • Imidazoles
  • Macrolides
  • Proton Pump Inhibitors
  • Sch 28080
  • Aldosterone
  • Ouabain
  • bafilomycin A1
  • H(+)-K(+)-Exchanging ATPase