Chemical Changes in Tumor-Bearing Mice. ∗

Summary

1. The nucleic acids, purines, pyrimidines, and methionine, arginine, histidine, threonine, glycine, and cystine have been determined in various tissues of mice of the Swiss strain bearing transplanted sarcoma 180 (Crocker). 2. The changes in the nucleic acid content of the tissues are paralleled by the values for the individual purines and pyrimidines. In the liver and lung of mice bearing sarcoma, there is an increase in both RNA and DNA, and this increase is further confirmed by the corresponding increases in uracil and thymine. The fact that only the DNA content of the kidney increases is further supported by an increase in the thymine values alone, while the uracil content of this organ remains unchanged. 3. The values for thymine when expressed as per cent of DNA, suggest that the composition of DNA in the liver, lung, and kidney is the same. 4. The study of the amino acids present in a sarcoma and in the tissues of normal and sarcoma-bearing mice reveals that there are significant changes in the amino acids of the tissues of tumor bearing animals. In the sarcoma, there is a significant increase in arginine and glycine, the values for the second and third week being higher than those for the first week. In the livers of these animals, there is a significant increase in arginine, histidine, threonine, glycine, and cystine over the normal controls. In the lung, the increase is noted in arginine, threonine, and cystine, while there is a drop in the histidine content, as the tumor progresses. Arginine alone shows a significant increase in the kidney, while in the spleen none of the amino acids studied shows any change over the normal control values.