Nucleic Acid Changes in Tumor-bearing Mice. ∗

Abstract

Summary

1. The nucleic acid content of various tissues has been determined in mice of the Swiss and dba strains bearing transplanted sarcoma 180 (Crocker), in dba mice bearing malignant melanoma S-91, and in Swiss mice bearing spontaneous mammary tumors. 2. In the mice with transplanted tumors, an increase in the pentose nucleic acid (RNA) and desoxypentose nucleic acid (DNA) content of the liver and lung was observed, whereas the kidneys showed a similar rise in the DNA. In the mice with mammary tumors, the most marked increase was found in the lung nucleic acids. 3. The changes of the nucleic acids in the dba mice could be related to the size and the rate of growth of the tumor. 4. The ratio RNA/ DNA in the tumor usually dropped with the growth of the tumor. This drop is attributed to a decreased concentration of RNA in both the necrotic and non-necrotic portions of the tumor, whereas the DNA content dropped only in the necrotic portion. 5. The nucleic acids, purines, and pyrimidines in malignant melanoma S-91 have been determined at various stages of its development. The lower values for uracil and thymine found in the necrotic portion of the tumor as compared with those found in the non-necrotic portion point also to a drop of both RNA and DNA in the necrotic portion.