Thiol-dependent K:Cl transport in sheep red cells: VIII. Activation through metabolically and chemically reversible oxidation by diamide.
The sulfhydryl (SH) oxidant diamide activated in a concentration-dependent manner ouabain-resistant (OR), Cl-dependent K flux in both low potassium (LK) and high potassium (HK) sheep red cells as determined from the rate of zero-trans K efflux into media with Cl or Cl replaced by NO3 or methane sulfonate (CH3SO3). Diamide did not alter the OR Na efflux into choline Cl. The diamide effect on K efflux appeared after 80% of cellular glutathione (GSH) was oxidized to GSSG, its disulfide. The stimulation of K efflux was completely reversed during metabolic restitution of GSH, a process that depended on the length of exposure to and the concentration of diamide. The action of diamide on both the K:Cl transporter and GSH was also fully reversed by the reducing agent dithiothreitol (DTT). Diamide apparently oxidized the same SH groups alkylated by N-ethylmaleimide (NEM) (Lauf, P.K. 1983. J. Membrane Biol. 73:237-246). Like NEM, diamide activated K:Cl transport several-fold more in LK cells than in HK cells, and the effect on LK cells was partially inhibited by anti-L1, the allo-antibody known to inhibit OR K fluxes.
Lauf
P K
PK
Department of Physiology and Biophysics, Wright State University, School of Medicine, Dayton, Ohio 45401-0927.
D000818:Animals; D001391:Azo Compounds / Q000494:pharmacology*; D002463:Cell Membrane Permeability / Q000187:drug effects*; D002712:Chlorides / Q000378:metabolism*; D003958:Diamide / Q000494:pharmacology*; D004229:Dithiothreitol / Q000494:pharmacology; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000378:metabolism*; D005033:Ethylmaleimide / Q000494:pharmacology; D005978:Glutathione / Q000378:metabolism*; D010042:Ouabain / Q000494:pharmacology; D010084:Oxidation-Reduction; D011188:Potassium / Q000378:metabolism*; D011817:Rabbits; D013438:Sulfhydryl Compounds / Q000378:metabolism
D001391:Azo Compounds; D002712:Chlorides; D013438:Sulfhydryl Compounds; D003958:Diamide; D010042:Ouabain; D005978:Glutathione; D005033:Ethylmaleimide; D011188:Potassium; D004229:Dithiothreitol