2l6 



ELECTROLYTES IN BIOLOGICAL SYSTEMS 



Quite obviously, the significant position of potassium in the mechanism of 

 active salt transport called for a more comprehensive study for the purpose of 

 arriving at some conclusion as to the physico-chemical state of potassium in skin 

 and of elucidating the relation between sodium ion transfer and potassium con- 

 tent of skin (29). By varying the potassium ion concentrations in the bath over 

 a relatively wide range, the dependence of intracellular on extracellular potas- 



n ^ 



A Na A CI A V 



A No A CI A V 



-80 



-100 .. 



RIGHT BAG IN RINGER'S 

 LEFT BAG IN RINGER'S 



I I RIGHT BAG IN RINGER'S I I 



^H LEFT BAG IN K*^FREE RINGER^Bl 



Fig. 7. Active salt and fluid transport by skin in complete Ringer's (left part of figure, 

 averages of 1 1 experiments) and by skin in K"'"-free Ringer's (right part of figure, averages of 

 8 experiments). Method of paired bags. Rana pipiens. Twelve hour experiments. Loss of 

 electrolytes and water from fluid compartment at epithelial side is indicated by negative 

 figures, gain of electrolytes is indicated by positive figures. Arbitrarily, changes in Na+ and 

 H2O in the left bag are set equal to 100. Other values are given in proportion to these refer- 

 ence values (26). 



slum has now been worked out; furthermore, the correlation between extra- 

 cellular potassium concentration and net active uptake and transport of sodium 

 chloride and water has been established. Data were obtained, simultaneously, 

 on intracellular sodium, movements of K"*" into or out of skin and also on skin 

 potentials. In these studies, saline solutions, pH = 7.4, contained NaCl, KCl, and 

 some NaHCOs. Three levels of NaCl were chosen, namely 48; 119; 169 /zEq/ml, 

 corresponding roughly to 0.4; i.o; 1.4 Ringer's. To these solutions, KCl was 



