[Reparative DNA synthesis in human and murine embryonic liver cell cultures treated with N-methyl-N'-nitro-N-nitrosoguanidine].

The carcinogenic agents--UV-light and N-methyl-N'-nitro-N-nitroso-guanidine (NMNG) were shown to induce DNA repair synthesis in human and mouse liver cell cultures. The DNA repair synthesis, measured autoradiographically, was less active in liver cells than in fibroblasts from the same embryo. The hepatocytes exhibited a higher resistance to the toxic effect of both UV-light and NMNG. This phenomenon is suggested to be due to the active non-excision DNA repair in liver cells.