A method for analysis of cellular K-transport mechanisms through thallium (201Tl) uptake in human lymphocytes.
Thallium (Tl) is the K-congener with the highest specific affinity to K-binding sites and the largest permeability in K-channels, and its usefulness for analysis of cellular K-transport mechanisms was investigated. The uptake of 201Tl was measured in cultured human lymphocytes (Jurkat cells and EBV-transformed B-cells) after various incubation conditions. In a complete culture medium the half-time of the Tl-uptake was 10 min at 37 degrees C and the steady state accumulation ratio (intracellular/extracellular) was c. 50. The steady state ouabain sensitive uptake was 81% in complete culture medium, it was reduced after substitution with Ringer solution and by a decrease in temperature (from 37 to 22 degrees C). The ouabain resistant uptake was higher at 22 degrees C than at 37 degrees C and it was almost completely inhibited in Na-free or Cl-free solution and by furosemide. The present results indicate that there are only two major routes for K-uptake in lymphocytes and that 201Tl may be a useful substitute for K in the analysis of cellular K-transport mechanisms.
Brismar
T
T
Department of Clinical Neurophysiology, Karolinska Hospital, Linköping, Sweden.
Lefvert
A
A
Jondal
M
M
D001402:B-Lymphocytes / Q000187:drug effects / Q000378:metabolism; D002460:Cell Line; D002461:Cell Line, Transformed; D005665:Furosemide / Q000494:pharmacology; D006801:Humans; D008214:Lymphocytes / Q000187:drug effects / Q000378:metabolism*; D010042:Ouabain / Q000494:pharmacology; D011188:Potassium / Q000378:metabolism*; D012965:Sodium Chloride / Q000494:pharmacology; D013601:T-Lymphocytes / Q000187:drug effects / Q000378:metabolism; D013696:Temperature; D013794:Thallium Radioisotopes / Q000493:pharmacokinetics
D013794:Thallium Radioisotopes; D012965:Sodium Chloride; D010042:Ouabain; D005665:Furosemide; D011188:Potassium