PURINE NUCLEOTIDE LEVELS IN HOST TISSUES OF EHRLICH ASCITES TUMOR-BEARING MICE IN DIFFERENT GROWTH PHASES OF THE TUMOR

The pool sizes of purine nucleotides, nucleosides, and nucleobases wer e measured in the host tissues liver, skeletal muscle, and blood of Eh rlich ascites tumor-bearing mice during the different periods of tumor growth. There were large differences of tissue concentrations of thes e metabolites between control animals, animals in the logarithmic grow th period of the Ehrlich ascites tumor, and animals in the resting pha se of tumor growth. The ATP concentrations in liver, muscle, and eryth rocytes were higher during the proliferating phase of the tumor compar ed with the ATP levels of these organs in healthy animals. In liver an d skeletal muscle the ATP concentration decreased during the transitio n from proliferating into resting phase of tumor growth. The concentra tions of nucleosides and nucleobases within the RBC and blood plasma d ecreased during the logarithmic growth phase but restored during the p lateau period. As well as in the organs/cells investigated and in the body fluids (plasma, ascites fluid) a tremendous increase of adenosine concentration during the resting phase of tumor growth was observed. From changes of total purine ribonucleotide pattern an activation peri od in the nucleotide metabolic pathways of liver and skeletal muscle d uring the proliferating phase of tumor growth is postulated.