title: DNA synthesis in tumor-bearing rats: purification of liver thymidine kinase stimulating factor from Yoshida sarcoma.
abstract: Yoshida sarcoma cells contain a factor that stimulates thymidine kinase activity in the liver of mice in vivo; intraperitoneal injection of an extract from Yoshida sarcoma into normal mice stimulated their liver thymidine kinase activity 2- to 3-fold, whereas injection of a crude extract of normal rat liver did not stimulate the activity at all. A factor that stimulates the de novo synthesis of thymidine kinase in the liver was partially purified from Yoshida sarcoma by ammonium sulfate fractionation, DEAE-cellulose column chromatography and gel filtration. It appeared to be thermolabile and sensitive to trypsin treatment. These results suggested that it was a high-molecular weight protein. Intraperitoneal injection of this factor into 67% hepatectomized rats stimulated thymidine kinase activity 2- to 3-fold. Increase of liver thymidine kinase activity after injection of the factor into mice was blocked by simultaneous injection of actinomycin-D. These results suggest that this factor stimulates de novo synthesis of thymidine kinase in the liver.
mesh_terms: D000818:Animals; D004247:DNA / Q000096:biosynthesis; D003609:Dactinomycin / Q000494:pharmacology; D008099:Liver / Q000201:enzymology*; D008115:Liver Regeneration; D008297:Male; D051379:Mice; D009363:Neoplasm Proteins / Q000302:isolation & purification; D051381:Rats; D012517:Sarcoma, Yoshida / Q000032:analysis* / Q000201:enzymology; D013937:Thymidine Kinase / Q000378:metabolism*
chemical_list: D009363:Neoplasm Proteins; D003609:Dactinomycin; D004247:DNA; D013937:Thymidine Kinase