SOLUBLE FACTORS FROM LIVER AND HEPATOMAS WHICH INHIBIT [H-3]THYMIDINE INCORPORATION INTO DNA OF NOVIKOFF HEPATOMA-CELLS

  • 1 January 1979
    • journal article
    • research article
    • Vol. 39  (5) , 1655-1660
Abstract
The nature of soluble factors from liver and hepatomas which inhibit [3H]thymidine incorporation into DNA was studied in [rat] Novikoff hepatoma cells. The decreased activity in hepatoma preparations was due to loss of a high MW heat-labile factor. Although this factor cochromatographed with arginase activity on Sephadex G-150, it does not appear to result from this activity as judged by the failure of arginine to prevent the inhibitory effect on [3H]thymidine incorporation. Both liver and hepatomas contained a heat-stable factor with inhibitory activity. Studies with ethanol-soluble material suggested that the action was not solely attributable to the presence of unlabeled thymidine, since the apparent MW was too high and since the factor(s) inhibited [3H]leucine incorporation into protein in addition to inhibition [3H]thymidine incorporation in DNA.