Metabolic alterations after total body doses of X-radiation: I. The role of regenerating liver nuclei and cytoplasm in the inhibition due to X-radiation of incorporation of tritium-labeled thymidine into DNA

The effect of X-radiation on the incorporation of [ 3H]TDR into the DNA of nuclei of reconstituted regenerating liver homogenates and into purified DNA incubated with irradiated and non-irradiated regenerating liver cytoplasm was studied. The results indicate that both the nuclei and the cytoplasm are affected by X-radiation but the effect is more marked on the cytoplasm than on the nucleus. These findings suggest that X-radiation interferes with the activity of the enzymes involved in the incorporation of nucleosides or nucleotides into the DNA.