Tumor Growth in Potassium-deficient Mice

The growth rate of Sarcoma 180 and of a mammary adenocarcinoma in potassium-deficient mice did not significantly differ from that in pair-fed control mice. The potassium concentration of these tumors in potassium-deficient mice was the same as in the control mice, although the potassium concentration of muscle and plasma was only half of that in the controls. The in vivo equilibration of K⁴²in Sarcoma 180 showed that at least 80 per cent of the tissue potassium was exchangeable.