title: Effect of split doses of N-methyl-N-nitrosourea on DNA repair synthesis in cultured mammalian cells.
abstract: DNA repair was measured in human fibroblasts, mouse C3H 10 T 1/2 fibroblsts and rat hepatocytes by the non-semi-conservative incorporation of [3H]-TdR during DNA repair synthesis using liquid scintillation techniques. Confluent monolayers of these cells grown on cover slips were exposed to split doses (125 or 250 microgram/ml) of the mutagenic and carcinogenic alkylating agent MNU and DNA repair synthesis compared with that produced by a single dose (500 microgram/ml). No significant difference in DNA repair capacity was detected in the three cell lines treated with a single dose or split doses of MNU.
mesh_terms: D002478:Cells, Cultured; D004247:DNA / Q000096:biosynthesis; D004260:DNA Repair / Q000187:drug effects*; D004334:Drug Administration Schedule; D008770:Methylnitrosourea / Q000008:administration & dosage / Q000494:pharmacology*; D009607:Nitrosourea Compounds / Q000494:pharmacology*
chemical_list: D009607:Nitrosourea Compounds; D008770:Methylnitrosourea; D004247:DNA