Effects of leukocyte-derived oxidants on sarcolemmal Na,K,ATP-ase and calcium transport.
Our study demonstrated that the Na,K,ATPase activity and ouabain binding sites were reduced by oxidants. Sarcolemmal calcium transport was also inhibited by hydrogen peroxide and HOC1. The action of HOC1 on the sarcolemmal functions was 2-3 orders of magnitude more powerful than that of hydrogen peroxide. Effects of hydrogen peroxide consisted of two components, i.e., the first, highly sensitive one, most probably mediated by Fe-catalyzed, site-specific free radical formation, and the second, less potent action by (high concentrations of) hydrogen peroxide. Finally, very low concentrations of hydrogen peroxide potentiated Na,K,ATPase activities when assayed using myocytes.
Matsuoka
T
T
Department of Physiology, University of Ottawa, Ontario, Canada.
Yanagishita
T
T
Kako
K J
KJ
D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D003676:Deferoxamine / Q000494:pharmacology; D004229:Dithiothreitol / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D006997:Hypochlorous Acid / Q000494:pharmacology*; D007679:Kidney Medulla / Q000201:enzymology; D007700:Kinetics; D007962:Leukocytes / Q000502:physiology*; D008314:Malonates / Q000494:pharmacology*; D008315:Malondialdehyde / Q000494:pharmacology*; D009206:Myocardium / Q000378:metabolism*; D010042:Ouabain / Q000378:metabolism; D051381:Rats; D012508:Sarcolemma / Q000187:drug effects / Q000378:metabolism*; D000254:Sodium-Potassium-Exchanging ATPase / Q000378:metabolism*; D013552:Swine
D008314:Malonates; D008315:Malondialdehyde; D010042:Ouabain; D006997:Hypochlorous Acid; D006861:Hydrogen Peroxide; D000254:Sodium-Potassium-Exchanging ATPase; D003676:Deferoxamine; D002118:Calcium; D004229:Dithiothreitol