Purine N-oxides. XVI. Oncogenic derivatives of xanthine and guanine.

The oxidation of guanine to an N-oxide and its hydrolysis to a xanthine N-oxide are rejorted. The s.c. administration of the xanthine N-oxide to rats for 6 months resulted in development of a variety of tumors. There were 1 liposarcoma, 3 fibrosarcomas, 1 nmmmary adenocarcinoma, 3 fibrohlastic tumors, 2 rhabdomyosarcomas, and 1 epideiinoid carcinoma at the site of injection and elsewhere in 11 out of 13 rats, or an iticidence of 85 @ The 1st measurable tumor appeared at 230 days and the last at 442 days @tfterthe 1st injection of the compound. The guanine N-oxide, injected s.c. for 6 months, but at a lower concentration, in duced 2 fibrosarcomas and 2 fibroblastic tumors in 15 rats; the 1st tumor appeared at 334 days and the last at. 445 days after the 1st injection of the compound. Administration of adenine 1-N-oxide for 6 months failed to produce tumors in any tissues of 13 rats during the experimental period of 15 months. Of 8 tumors induced by the xanthine N-oxide, 7 were transplantable, and serial traits