Ion transport by ouabain resistant and sensitive ehrlich ascites carcinoma cells

Cell division, net Na + ‐K + and amino‐acid transport of cultured Ehrlich ascites is reversibly inhibited by Ouabain at a final concentration of 1 × 10 –3 M. A line of Ehrlich ascites cells resistant to the growth inhibiting effects of Ouabain has been developed. These cells behave similarly to Ouabain‐sensitive cells in the following respects doubling time, S phase time, chromosome number, cell surface charge density, rate of incorporation of C 14 Uridine and 3 H‐Thymidine, sensitivity to Digoxin and Digitoxin, steady state Na + , K + levels and rate of loss of K + and gain of Na + in cold. Ouabain resistant cells differ from sensitive cells only with respect to the effect of ouabain on active Na + , K + transport. Although Ouabain inhibits active Na + , K + transport in sensitive cells it has no significant effect in resistant cells.