Methodological assessment of assays for intracellular concentration and transmembrane fluxes of sodium and potassium in erythrocytes of man.
The reliability of the assay of intracellular Na+ and K+ concentration; Na+,K+-ATPase activity; Na+-K+ cotransport and Na+-Li+ countertransport in erythrocytes was investigated. These assays were also applied in normal male subjects with and without family history of hypertension. The various assays are reproducible as indicated by the intra-assay variation and are stable over time as shown by the inter-assay variation. A delay between blood sampling and analysis, however, result in an increase in intracellular Na+ concentration and decreases in Na+,K+-ATPase activity; Na+-K+ cotransport and Na+-Li+ countertransport. Compared to the white normal males without family history of hypertension (n = 43) red blood cells of white normal males with such a history (n = 17) have a higher (p less than 0.01) intracellular Na+ concentration. This can be at least partly due to their lower (p less than 0.001) furosemide-sensitive Na+ efflux rate. Also, their ouabain-resistant 86Rb-uptake was lower (p less than 0.05). The potassium concentration in the red blood cells was similar in both groups.
D000328:Adult; D001692:Biological Transport; D001800:Blood Specimen Collection; D004912:Erythrocytes / Q000032:analysis* / Q000378:metabolism; D005665:Furosemide / Q000494:pharmacology; D006801:Humans; D008094:Lithium / Q000378:metabolism; D008297:Male; D011188:Potassium / Q000097:blood*; D012044:Regression Analysis; D012413:Rubidium / Q000378:metabolism; D012964:Sodium / Q000097:blood*; D000254:Sodium-Potassium-Exchanging ATPase / Q000097:blood; D013997:Time Factors
D005665:Furosemide; D008094:Lithium; D012964:Sodium; D000254:Sodium-Potassium-Exchanging ATPase; D012413:Rubidium; D011188:Potassium