Evaluation of ouabain-insensitive red blood cell cation transport in uremic patients.
The authors present the results of a simultaneous assay of: intracellular Na+ and K+ concentrations, Na+ and K+ outward bumetanide-sensitive effluxes (Na+, K+ cotransport), Na+ efflux stimulated by extracellular Li+ (Na+, Li+ countertransport), and ouabain- and bumetanide-resistant Na+ and K+ effluxes (passive membrane permeability) performed in red blood cells from 15 uremic patients an regular hemodialysis and from 12 normal subjects, with an established flux assay. Na+ and K+ effluxes by the Na+, K+ cotransport system were significantly (p less than 0.01) lower in uremic patients then in normals (219 +/- 37 vs 82 +/- 17 mumol/l RBC/h and 251 +/- 29 vs 139 +/- 14 mumol/l RBC/h respectively). In normal subjects the bumetanide sensitive Na+ and K+ effluxes were strongly (r = 0.89; p less than 0.01) intercorrelated; and the intracellular Na+ concentration was related to the outward Na+ cotransport flux (r = 0.53; p approximately 0.05). Among uremic patients these correlations were not found. Na+ and K+ intracellular concentrations, passive Na+ and K+ permeability, and Na+, Li+ countertransport activity were not different among uremic patients and normal controls. In conclusion, in uremic dialyzed patients, red blood cell Na+, K+ cotransport activity is quite uniformly suppressed. The possible pathogenesis of this disfunction is still speculative and deserves further studies.
D000328:Adult; D000368:Aged; D002463:Cell Membrane Permeability / Q000187:drug effects; D004910:Erythrocyte Membrane / Q000378:metabolism*; D005260:Female; D006801:Humans; D006973:Hypertension / Q000097:blood; D008094:Lithium / Q000097:blood; D008297:Male; D008563:Membrane Lipids / Q000378:metabolism; D008875:Middle Aged; D010042:Ouabain / Q000494:pharmacology; D010084:Oxidation-Reduction; D011188:Potassium / Q000097:blood; D006435:Renal Dialysis; D012964:Sodium / Q000097:blood; D014511:Uremia / Q000097:blood*
D008563:Membrane Lipids; D010042:Ouabain; D008094:Lithium; D012964:Sodium; D011188:Potassium