The conservation of ribonucleic acid by Ehrlich ascites tumor cells

Essentially all of the 14C of orotic acid-6-14C incorporated into te pyrimidines of RNA and DNA of Ehrlich mouse ascites tumor cells (hyperdiploid and tetraploid lines) is retained for periods of 7–10 days in vivo during which the cells are increasing six-fold in number at a logarithmic rate. This result is observed whether the cells are maintained in the animals in which the labeling is effected or whether the labeled cells are removed to hosts which have received no radioactivity.