Arabinosyladenine and arabinosylhypoxanthine metabolism in murine tumor cells

The in vitro metabolism of 9-β-D-arabinofuranosyladenine (Ara-A) in TA3 ascites tumor cells was examined and compared with that of its metabolite 9-β-D-arabinofuranosylhypoxanthine (Ara-H). Some evidence for reamination of Ara-H to Ara-A was obtained. Such reamination may explain its activity as an antiviral agent. Unlike Ara-A, Ara-H was not phosphorylated and it did not inhibit DNA polymerase. Incorporation of radioactivity from Ara-A-14C or Ara-H-14C into RNA occurred, but was shown to have proceeded by a cleavage to free base and efficient reutilization of the labeled base.