Originally published in Acta Fhysiol. Scand 3, 193 (1942) 



50. RATE OF PENETRATION OF IONS INTO 

 ERYTHROCYTES 



L. Hahn and G. Hevesy 



From the Institute of Theoretical Physics, University of Copenhagen 



The hindrance which an ion encounters when passing the phase boundary 

 can be measured by measuring the rate at which labeUed and non- 

 labelled ions interchange through the phase boundary. When one phase 

 contains ^^Na ions, the other phase besides 23Na ions also ^^Na ions of 

 negligible weight, we obtain by determining the rate at which ^'^Nsi 

 penetrates into the second phase a correct measure of the hindrance 

 which sodium ions encounter when passing the phase boundary and, 

 thus, a correct measure of the permeability of the phase boundary to 

 sodium ions if only we perform the experiment in such a way that the 

 amount of ^^Na returning from the second phase into the first phase 

 can be disregarded. In this paper, the rate of interchange of phosphate, 

 chloride, and sodium between plasma and corpuscles is discussed. 



PENETRATION OF LABELLED PHOSPHATE INTO THE CORPUSCLES 



OF THE RABBIT 



We extended our former measurements (Aten and Hevesy 1938, 

 1939; Hahn and Hevesy, 1938, 1940) by further experiments on the 

 penetration of labelled phosphate into the corpuscles. The distribution 

 of 32p between corpuscles and plasma of equal weight is seen in Fig. 1. 

 In these experiments, the ^^P was added as sodium phosphate of negligible 

 weight to rabbit blood. The blood to which ammonium oxalate or heparin 

 w^as added was saturated with a mixture containing 5 p.c. COg and 95 

 p.c. O2 and shaken in the thermostat kept at 37. Corpuscles and 

 plasma were separated by centrifuging sharply and the activity of the 

 fractions obtained was compared. W^e omitted washing of the corpuscles, 

 since such a procedure may lead to a removal of some of the ^-P present 

 in the corpuscles. 



To determine the amount of plasma adhering to the centrifuged cor- 

 puscles we w'ashed, in test experiments, the corpuscles thoroughly with 

 a physiological sodium chloride solution and determined the nitrogen 



