[The effect of inhibitors of ionic passive transport on the structure of a cell population of Ehrlich's ascites carcinoma].

: Triampur is a drug, containing triamterene and dichlotiazide, which inhibits passive influx of Na+ through cell membrane. Triampur was injected intraperitoneally to mice with the Ehrlich ascite carcinoma. The drug was injected in the exponential phase of tumor growth with 2 hour intervals within 24 hours. A subsequent sedimentation and fractionation of cells according to the cell cycle position displayed an additional peak in sedimentogram, that was absent in the control sedimentogram. This peak is due to cell blocking in G1-period; the pool of blocked cells contains 20-25% of the total cell population. If the drug was injected during 3 days and nights with 8-hour intervals, the pool of blocked cells amounted up to 40%. This effect is reversible: when the drug is cancelled, the peak of G1-blocked cells is reduced. Estimation of intracellular Na(+) and K(+) concentration and Na+, K(+) pump indicates a significant decrease in Na+ permeability in the blocked cells due to Triampur effect. The obtained data well compare with an idea of the importance of increasing a passive influx of Na+ for G1-S transition, and indicate a possibility to affect the structure of tumor cell population via the system of intracellular ionic homeostasis.