Abstract
Tumor-bearing mice were subjected to short-term treatment with various purine and folic acid antagonists, then sacrificed for quantitative assay of tissue adenine nucleotides. 6-Mercaptopurine somewhat lowered the levels of ATP, total nucleotide, and the sum of known mucleo-tides, in liver and muscle, and to a lesser extent in spleen and tumor tissues. 8-Azaguanine raised total nucleotide levels in liver and tumor tissue, but not in muscle or spleen. 6-Diamino-purine was essentially without effect on nucleotide levels in these tissues. Aminopterin elevated slightly the ATP level in liver but was without effect on ATP in spleen or muscle. In tumor tissue, aminopterin reduced the ATP level by nearly 50% and, when used concurrently with adenylic acid, by nearly 70%.