The Effects of Potassium Deficiency on Tumor-Bearing Mice *

Many attempts have been made to influence the growth of tumors by altering the amount or quality of the diet. In the experiments reported here, the effect of eliminating potassium, an element essential to growth of the body, upon a transplantable carcinoma of the mouse was investigated. The results of potassium deprivation have been extensively studied. Miller10 found that when the potassium content of the food of young rats weighing between 40 and 60 gm. was reduced below 0.1 per cent their growth was greatly retarded. In subsequent work1' Miller reported that the potassium requirement for the growth of the male was almost twice that of the female; the amount required for maintenance of a mature rat was Y8 that of the growing male. Lesions in the heart and other organs of rats after deprivation of potassium were described by Schrader, Prickett, and Salmon."3 Thomas, Mylon, and Winternitz"8 found that the myocardial lesions in the rat depended on an associated deficiency of vitamin B6. No other anatomical changes were noted by these observers. Chemical analyses of deficient rats by Heppel' showed marked depletion of muscle potassium with replacement by sodium; liver, however, was discovered to be tenadous of its potassium. Analysis of tumor tissue has shown in general an increase in potassium which is roughly proportional to the rate of growth."4'6" 19 On the other hand, when normal or malignant cells are deprived of potassium in vitro they fail to grow.'7 These observations have been the stimulus to the present work.