Nuclei from Normal and Leukemic Mouse Spleen II. The Nucleic Acid Content of Normal and Leukemic Nuclei

Nuclei have been isolated from the spleens of mice bearing spontaneous or transplanted leukemia. In spontaneous leukemia, which develops slowly, the PNA per nucleus is increased to 1.6 times the normal amount, and there is no change in DNA or nitrogen. In transplanted leukemia, which develops rapidly, the PNA, DNA, and nitrogen per nucleus are increased to 4.2, 1.45, and 1.69 times their respective amounts in normal spleen. The differences in nucleic acid content found in the nuclei from the transplanted leukemia are similar to those reported for rapidly growing tissues, while the nuclei from the spontaneous leukemia more closely resemble the normal nuclei. Thus, the changes seem to be characteristic of rapid growth rather than of any primary neoplastic process.