138 



ELECTROLYTES IN BIOLOGICAL SYSTEMS 



is without effect on cation distribution in human red cells. Both of these com- 

 pounds have a large effect on amino acid and electrolyte distribution in tumor 

 cells (7). Thus, no clear relation between amino acid metabolism and cation 

 transport in human red cells is evident at the present time. 



Solomon et al. (loi) have recently presented evidence that a factor present 

 in plasma is necessary for normal K transport in human red cells. This factor 

 is necessary only when the concentration of K in the medium is less than about 

 2 mM/1. The identity of the plasma factor as well as its mode of action are not 

 yet clear. 



A wide variety of lytic agents produce K loss and Na gain prior to hemolysis 

 (80-83). Among these are certain alcohols, dyes and radiation. Large doses of 

 x-rays produce K loss primarily by increasing K outflux (93, 97). Pb salts also 



Table 2. K influx by diffusion and by carrier 



cause a rapid net loss from human red cells (i, 69). It is probable that most 

 of these agents act by reducing the resistance of the cell membrane to cation 

 diffusion. Support for this conclusion will be outlined in the section on K trans- 

 port in human red cells exposed to n-butanol. 



Human Red Cells Exposed to n-Butanol. Jacobs (49) suggested and Ponder 

 (82) has shown experimentally that n-butanol causes human red cells to lose 

 the capacity to selectively retain K and exclude Na. Hoffman and Tosteson (44) 

 have recently studied the kinetics of K transport in human red cells exposed 

 to 0.3 m/1. n-butanol at 25°C. 



Flux ratio analysis. The ratio of inward to outward K rate constant for cells 

 exposed to 0.3 m/1. butanol is shown in table i. This ratio closely approximates 

 that which would be predicted for diffusion. The value of D'k calculated from 

 the flux ratio analysis is 2.65, more than 100 times greater than the value for 

 D'k in normal human red cells (table 2). This calculation was made assuming 



