Pflügers Archiv

, Volume 416, Issue 5, pp 540–547

Madin-Darby canine kidney cells

III. Aldosterone stimulates an apical H+/K+ pump
  • H. Oberleithner
  • W. Steigner
  • S. Silbernagl
  • U. Vogel
  • G. Gstraunthaler
  • W. Pfaller
Transport Processes, Metabolism and Endocrinology; Kidney, Gastrointestinal Tract, and Exocrine Glands

DOI: 10.1007/BF00382687

Cite this article as:
Oberleithner, H., Steigner, W., Silbernagl, S. et al. Pflügers Arch. (1990) 416: 540. doi:10.1007/BF00382687

Abstract

Functionally and morphologically, Madin-Darby canine kidney (MDCK) cells resemble intercalated cells of urinary epithelia. Experiments were performed on domes of confluent MDCK monolayers to test for apical H+ secretion. Apical application of 10−3 mol/l amiloride or of Na+-free solution significantly reduced the limiting pH gradient across the dome epithelium (Δ pHd) consistent with inhibition of apical Na+/H+ exchange. Short-circuit current (SCC) measurements disclosed an acetazolamide-sensitive, (basolateral to apical) positive transepithelial current stimulated by 10−7 mol/l aldosterone and inhibited by acidification of apical medium to pH=4.5. Histochemical evaluation of carbonic anhydrase (CA) activity revealed cytoplasmic and apicalmembrane-bound CA particularly in dome-forming cells. Apical substitution of Na+ by K+ increased Δ pHd, whereas a reduction of K+ concentration to 0.5 mmol/l or addition of barium or omeprazole (10−5 mol/l) to the apical superfusate reduced Δ pHd by at least 75%. Aldosterone-stimulated SCC was completely abolished by the apical application of barium. We conclude that besides Na+/H+ exchange MDCK cells can express an apically located H+-K+ pump stimulated by aldosterone and inhibited directly by the anti-ulcer agent omeprazole or indirectly, either by blocking apical K+ recycling or by interfering with the CA-dependent intracellular formation of H+ ions.

Key words

MDCK cellsOmeprazoleH+-K+ pumpCarbonic anhydraseIntercalated cells

Copyright information

© Springer-Verlag 1990

Authors and Affiliations

  • H. Oberleithner
    • 1
  • W. Steigner
    • 1
  • S. Silbernagl
    • 1
  • U. Vogel
    • 1
  • G. Gstraunthaler
    • 2
  • W. Pfaller
    • 2
  1. 1.Department of PhysiologyUniversity of WürzburgWürzburgGermany
  2. 2.Department of PhysiologyUniversity of InnsbruckInnsbruckAustria