[Radioactivity of an acid-soluble liver fractions after administration of 3H-thymidine for the purpose of explaining the reasons for delayed DNA labeling].

When 3H-thymidine is injected 24 hours before a partial hepatectomy, the radio-activity of acid-soluble fraction in the mouse liver begins to rise after the operation. When 3H-thymidine is injected to animals immediately after the operation or to unoperated animals, no such a rise is recorded. The maximal radioactivity of acid-soluble fraction of the liver is observed 28 hours after hepatectomy, at the moment preceding the commencement of DNA synthesis in a great number of hepatocytes. This increase is in conformity with the subsequent rise of DNA radioactivity. It is suggested that cells of the regenerating liver reutilize the degradation products of labeled DNA which become a source of DNA late labeling.