Liver nitrogen in tumor-bearing rats.

In a previous study of tumor-bearing rats of the Wistar strain (1@), it was shown that the growth of a neopla.sm elsewhere than in the liver itself was frequently accompanied by an increase in the weight of the liver. It was recognized that the per centage of liver water was increased in such am mals (4, 8); but, according to McEwen and Haven (8), the dry livers of rats with subcutaneous im plants of carcinosarcoma @56 were not significantly heavier than those of control animals. However, the dry weight may not be a reliable indication of the protein content, inasmuch as Kosterlitz (7) has shown that an alteration in liver nitrogen corn ponents may be accompanied by an opposite change in the amount of glycogen or fat or both, with the result that little or no change is de tectable in the total dry weight. Recently, a report by Sherman, Morton, and Mider (10) showed that the livers of cancerous rats acquired nitrogen dur ing a part of the period of tumor growth. The pres ent study indicates that, in rats with subcutaneous tumors of varying sizes, (a) the nitrogen of the liver increased significantly when large growths were present and (b) the degree to which the nitro gen accumulated was proportional to the total mass of the rat—that is, to the weight of the car cass plus the weight of the tumor.