Sch-28080 depletes intracellular ATP selectively in mIMCD-3 cells

Am J Physiol Cell Physiol. 2000 Nov;279(5):C1319-26. doi: 10.1152/ajpcell.2000.279.5.C1319.


Two H(+)-K(+)-ATPase isoforms are present in kidney: the gastric, highly sensitive to Sch-28080, and the colonic, partially sensitive to ouabain. Upregulation of Sch-28080-sensitive H(+)-K(+)-ATPase, or "gastric" H(+)-K(+)-ATPase, has been demonstrated in hypokalemic rat inner medullary collecting duct cells (IMCDs). Nevertheless, only colonic H(+)-K(+)-ATPase mRNA and protein abundance increase in this condition. This study was designed to determine whether Sch-28080 inhibits transporters other than the gastric H(+)-K(+)-ATPase. In the presence of bumetanide, Sch-28080 (200 microM) and ouabain (2 mM) inhibited (86)Rb(+) uptake (>90%). That (86)Rb(+) uptake was almost completely abolished by Sch-28080 indicates an effect of this agent on the Na(+)-K(+)-ATPase. ATPase assays in membranes, or lysed cells, demonstrated sensitivity to ouabain but not Sch-28080. Thus the inhibitory effect of Sch-28080 was dependent on cell integrity. (86)Rb(+)-uptake studies without bumetanide demonstrated that ouabain inhibited activity by only 50%. Addition of Sch-28080 (200 microM) blocked all residual activity. Intracellular ATP declined after Sch-28080 (200 microM) but recovered after removal of this agent. In conclusion, high concentrations of Sch-28080 inhibit K(+)-ATPase activity in mouse IMCD-3 (mIMCD-3) cells as a result of ATP depletion.

Publication types

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

MeSH terms

  • Adenosine Triphosphate / antagonists & inhibitors*
  • Animals
  • Bumetanide / pharmacology
  • Cell Line
  • Drug Synergism
  • Enzyme Inhibitors / pharmacology*
  • Humans
  • Imidazoles / pharmacology*
  • Intracellular Membranes / metabolism*
  • Kidney Medulla
  • Kidney Tubules, Collecting / cytology
  • Kidney Tubules, Collecting / metabolism*
  • Mice
  • Ouabain / pharmacology
  • Rubidium / antagonists & inhibitors
  • Rubidium / pharmacokinetics
  • Sodium-Potassium-Exchanging ATPase / antagonists & inhibitors


  • Enzyme Inhibitors
  • Imidazoles
  • Sch 28080
  • Bumetanide
  • Ouabain
  • Adenosine Triphosphate
  • Sodium-Potassium-Exchanging ATPase
  • Rubidium