Pyrimidine Metabolism in Tissue Culture Cells Derived from Rat Hepatomas. I. Suspension Cell Cultures Derived from the Novikoff Hepatoma.

hepatomas have demonstrated that a spectrum of such tumors exists with varying degrees of change from the parent hepatocyte (26—30). Such hepatocarcinomas as the Morris 5123 (18) and Reuber H-35 (34), for instance, resemble the parent tissue to a marked degree both morphologically and biochemically (27), and thus fall in the category termed “minimaldeviation hepatomas― by Potter (31). On the other hand, tumors such as the Novikoff hepatoma differ in so many respects from the parent tissue that one can only speculate as to their cell oforigin. In undertaking a program of comparative enzyrnology of such a diverse spectrum of tumors in the intact host, serious difficulties arise in terms of both experimental design and interpretation of data. Among these are the problem of distinguishing effects due to the intrinsic bio