146 ELECTROLYTES IN BIOLOGICAL SYSTEMS 



transport in duck cells incubated in N2 . Removal of phosphate from the 

 medium in the presence or absence of 30 mM/1. NaF also is ineffective. Diamox 

 (6063), a carbonic anhydrase inhibitor, is without effect. K influx is less at pn 

 7.0 than at pn 7.5 for duck cells incubated in N2 . 



Maizels (60) has recently reported experiments on the net re-accumulation 

 of K and extrusion of Na in cold stored K-deficient, Na-rich chicken red cells 

 upon incubation with substrate at 37° in oxygen. He found that Na extrusion 

 and accumulation of K were blocked by cyanide (0.6 mM/1.), dinitrophenol 

 (0.06 mM/1.), malonate (gmu/l.), fiuoracetate (10 mM/1.), and replacement of 

 O2 in the system with N2 or CO. NaF and lAA blocked the process when glu- 

 cose was the substrate but lactate reversed the inhibition. The effect of NaF 

 was partially prevented by plasma, presumably because of the lactate it con- 

 tained. 10 mM/1. glutamate had no effect on the net transport of K and Na. He 

 concluded that respiration but not glycolysis supports cation transport in 

 chicken erythrocyte. 



The explanation for the inhibition of net K accumulation by anoxia in 

 chicken cells in contrast to the stimulated steady state K influx observed in 

 duck cells in N2 is not clear. It could be due to a species difference, or to a 

 difference in the experimental methods employed. We have recently measured 

 net re-accumulation and K fluxes in duck cells which had been stored over- 

 night in a K-free, glucose-free medium at 37°C in either O2 or N2 . As men- 

 tioned above, prolonged incubation in N2 in the absence of glucose produced a 

 marked inhibition of both K influx and outflux. Therefore, it was not surpris- 

 ing to find that net re-accumulation of K failed to occur when duck cells which 

 had been stored overnight in N2 were re-incubated in N2 in glucose enriched 

 medium containing 10 mM/1. K. When the cells which had been stored over- 

 night in O2 were incubated in the restoring medium, both net re-accumulation 

 and influx of K were faster when the restoring gas phase was N2 than when it 

 was O2 . Thus, the fact that Maizels (60) stored his cells overnight in N2 

 before doing his anoxia experiments may account for the fact that net re- 

 accumulation of K failed to occur in cells incubated in the absence of O2 . In 

 any case, it is evident that respiration is not required for support of potassium 

 transport in duck red cells. 



prskov (70) has recently studied net K accumulation in pigeon red cells. He 

 found that cells in heparinized pigeon blood take up K from the plasma when 

 incubated at 43°C in air. When the air was replaced with CO2 , the process 

 did not occur, and, in fact, the cells rapidly lost K and gained Na. Return to 

 O2 caused the cells to re-accumulate K and extrude Na. Interpretation of this 

 experiment is difficult due to the marked uncontrolled changes in pn produced 

 by 100% CO2 which occurred simultaneously with the removal of O2 . How- 

 ever, the elimination of O2 by incubating in a closed flask with no gas phase 

 also produced K loss from the cells with subsequent re-accumulation upon 



