title: Soluble factors from liver and hepatomas which inhibit [3H]thymidine incorporation into DNA of Novikoff hepatoma cells.
abstract: The nature of soluble factors from liver and hepatomas which inhibit [3H]thymidine incorporation into DNA was studied in Novikoff hepatoma cells. The decreased activity in hepatoma preparations was due to loss of a high-molecular-weight 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 molecular weight was too high and since the factor(s) inhibited [3H]leucine incorporation into protein in addition to inhibiting [3H]thymidine incorporation in DNA.
mesh_terms: D000818:Animals; D001119:Arginase / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism; D004273:DNA, Neoplasm / Q000096:biosynthesis*; D005260:Female; D006358:Hot Temperature; D008099:Liver / Q000378:metabolism*; D008114:Liver Neoplasms, Experimental / Q000378:metabolism*; D008297:Male; D008970:Molecular Weight; D051381:Rats; D013936:Thymidine / Q000378:metabolism
chemical_list: D004273:DNA, Neoplasm; D001119:Arginase; D013936:Thymidine