THE EFFECT OF LOW TEMPERATURES UPON INTRACEL- 

 LULAR POTASSIUM IN ISOLATED TISSUES * 



1. M. TAYLOR 

 (Read by E. CALKINS) 



In the last fifteen years it has been repeatedly demonstrated that the distribution 

 of sodium and potassium between intracellular and extracellular fluids in living 

 tissues is controlled by the metabolic activity of the cells themselves/- - Dr. Renkin 

 and I, working independently, have been interested in the effect of hypothermia upon 

 these cation distributions and are going to discuss some aspects of this phase of the 

 problem of hypothermia. Each of us will present some of his experimental material 

 which is pertinent. 



The fundamental phenomena in which we are interested can be summarized 

 briefly. In almost all living tissues, sodium and potassium, the two most abundant 

 tissue cations, are distributed in a characteristic fashion, potassium being the pre- 

 dominant intracellular cation and sodium being its counterpart outside the cell. This 

 separation is not accomplished by the interposition of a barrier (the cell membrane) 

 which is impermeable to the cations. On the contrary, studies with radioactive 

 tracers show that interchange of these and presumably other ions across this mem- 

 brane is taking place constantly. This implies the expenditure of energy for main- 

 taining the concentration gradients, a concept borne out empirically l)y many ex- 

 periments which show that interference with the metabolism of the cell results in 

 disturbance of the electrolyte distributions. 



Subjecting tissues to hypothermia is one way of interfering with the metabolism 

 of the cells and for a variety of tissues from homeothermic animals, it has been 

 shown that low temperatures will induce escape of potassium from and entrance of 

 sodium into the intracellular phase, in the direction of thermodynamic equilibrium. 

 Cultured embryonal tissues from chickens,' guinea pig retina and brain slices,* 

 human erythrocytes,'' and hemidiaphragms from rats, have all been shown to lose 

 intracellular potassium when incubated at low temperatures under conditions which 

 in other respects (except for the temperature) are identical with those permitting 

 incubation for several hours or even days at 37° C. without disturbance of intra- 

 cellular potassium concentration. 



It may be remarked here that most of the studies cited, and the experiments which 

 I shall describe, have been directed for technical reasons at potassium, the intra- 

 cellular cation, and that for the purposes of my discussion there are adequate rea- 

 sons to assume an opposite movement of sodium even in the experiments in which 

 sodium has not been actually measured. That is, net loss of potassium from the 

 intracellular space may justifiably be considered to be accompanied by simultaneous 

 entrance of sodium into the cell. 



Is there a relation between the loss of potassium from these tissues under condi- 

 tions of hypothermia and the lethal effects of hypothermia in the intact homeother- 



* The experiments reported in this paper were performed under contract with the Department 

 of tlie Army. 



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