The conversion of 1,3-N15-,2-c14-adenine to polynucleotide adenine and guanine in the adult male rat

1,3-N¹⁵ -,2-C¹⁴ -adenine was synthesized and administered to rats by intraperitoneal injection. The compound was incorporated as both adenine and guanine into the visceral nucleic acids. Comparison of the C¹⁴/N¹⁵ ratios found in the adenine and guanine isolated from the visceral nucleic acids with that in the injected adenine indicated that for both compounds there had been a loss of C¹⁴ . The decrease in the C¹⁴/N¹⁵ ratio of the polynucleotide guanine was much greater than that in the polynucleotide adenine. The inference drawn from this marked difference was that on at least one pathway for the conversion of adenine to guanine the purine nucleus does not remain intact. The labile 2-C¹⁴ was found as C¹⁴ O₂ in the animals' expired air. Evidence that part of the C¹⁴ O₂ resulted from purine interconversion was afforded by examining the allantoin excreted in the animals’ urine. This compound had a C¹⁴/N¹⁵ ratio consistent with the source from which it was derived, the nucleic acid purine. The deficit of C¹⁴ , apparent from the C¹⁴/N¹⁵ ratio, in this excretory product for 47% of the C¹⁴ O₂ expired by the animals.Medicine, Faculty ofBiochemistry and Molecular Biology, Department ofGraduat