Early utilization of adenine and formate by mouse ascites tumor cells in vivo

Abstract

A tracer dose of adenine-8- 14C injected intraperitoneally into mice with Ehrlich-Landschütz (hyperdiploid) ascites tumors was rapidly taken up by the tumor cells (89% after 2 minutes, 98% after 5 minutes). The adenine was equally rapidly incorporated into the nucleotide fraction of the cells, less than 5% of the total cellular activity remaining as free adenine after 2 minutes. A decrease in the radioactivity of the total acid-soluble and total nucleotide fractions occured over the interval of 2–40 minutes after injection, while during this time the total acid-insoluble, RNA and DNA activities increased. Neither barbiturate anesthesia of the host nor X-irradiation with 350 R 2 minutes before injection had any effect on the uptake or incorporation of adenine by the tumor cells when measured 10 minutes after the injection. Intraperitoneally-administered formate- 14C was taken up and utilized by the tumor cells more slowly than was adenine, but over the interval of 10–40 minutes after injection it was incorporated into all fractions investigated. Changes in the specific and total activities of adenine and guanine with time were measured in the various fractions and the metabolic pathways indicated by the above findings considered.