K depletion modifies the properties of Sch-28080-sensitive K-ATPase in rat collecting duct

Am J Physiol. 1997 Jan;272(1 Pt 2):F124-31. doi: 10.1152/ajprenal.1997.272.1.F124.


Two distinct Sch-28080-sensitive K-adenosine triphosphatases (K-ATPases) were previously described in the rat nephron: a ouabain-resistant K-ATPase (type I) present in collecting ducts (CD) and a ouabain-sensitive from (type II) located in proximal tubules (PT) and thick ascending limbs (TAL). In K-depleted rats, K-ATPase activity is increased in CD, whereas it is reduced in PT and TAL. Because expression of colonic H-K-ATPase is restricted to the CD of K-depleted rats, we hypothesized that K-ATPase from the CD of K-depleted rats might be different from types I and II. Indeed, type III K-ATPase displays higher sensitivities to ouabain and to Sch-28080 than type II, a lower sensitivity to Sch-28080 than type I, and, conversely to types I and II, it can be stimulated by Na+. Pharmacological differences between types II and III K-ATPases were confirmed by [3H]ouabain binding experiments. Thus the rat kidney expresses three K-ATPases that differ by their pharmacological and kinetic properties, their distribution profile along the nephron and their behavior during K depletion.

MeSH terms

  • Adenosine Triphosphatases / antagonists & inhibitors
  • Adenosine Triphosphatases / drug effects*
  • Adenosine Triphosphatases / metabolism*
  • Animals
  • Cation Transport Proteins
  • Dose-Response Relationship, Drug
  • Enzyme Inhibitors / pharmacology*
  • H(+)-K(+)-Exchanging ATPase
  • Imidazoles / pharmacology*
  • Kidney Tubules, Collecting / metabolism*
  • Nephrons / metabolism
  • Ouabain / metabolism
  • Ouabain / pharmacology
  • Potassium Deficiency / metabolism*
  • Rats
  • Rats, Wistar
  • Sodium / pharmacology
  • Tissue Distribution


  • Cation Transport Proteins
  • Enzyme Inhibitors
  • Imidazoles
  • Sch 28080
  • Ouabain
  • Sodium
  • Adenosine Triphosphatases
  • potassium transporting ATPase
  • H(+)-K(+)-Exchanging ATPase