Effects of 4-aminopyrazolo (3,4-d)pyrimidine and 1-methyl-4-aminopyrazolo(3,4-d)pyrimidine on nucleic acid purine metabolism in ascites tumors.

The effect of a single injection of a therapeutic level of either 4-aminopyrazÃ3lo(3,4rf)pyrimidine or l-methyl-4-aminopyrazolo(3,4-¿)pyrimidine on the incorporation of glycine-C14, adenine-C14, or guanine-C14 into RNA and DNA adenine and guanine during the 12-hour period after drug administration has been studied in the Ehrlich ascites carcinoma, which is sensitive to both drugs, and in Sarcoma 180, which is re sistant to both. The results obtained show a rather complex series of events, varying markedly over the time course studied and often characterized by marked stimulations of isotope incorporation. Such effects lead to the tentative conclusions that the effects of these drugs are at the acid-soluble nucleotide level and that marked alterations occur in the pool sizes of these nucleotides.