The distribution of radioactivity following the feeding of carbon 14-labeled 2-acetylaminofluorene to rats.

Summary The distribution of radioactivity was studied in rats following oral administration of a single dose of 2-acetylaminofluorene-9-C14 at 2 and 6 hours, and 2-acetylaminofluorene-ω-C14 at 6 hours. A considerable quantity of the administered radioactivity of 2-acetylaminofluorene-9-C14 was absorbed within 2 hours, with detectable quantities present throughout the body of the rat. A wide distribution of radioactivity was also noted at 6 hours, after administration of either compound. However, the path taken by the radioactivity of the 9-labeled compound was different from that of the methyl-labeled derivative. Less of the latter was excreted in the urine, and more was found in the organs and tissues. Six per cent of the administered radioactivity from 2-acetylaminofluorene-ω-C14 was eliminated in the breath within 6 hours, while negligible amounts of radioactivity from the 9-C14-labeled compound were expired during the same period, which supports the view that the acetyl group of 2-acetylaminofluorene is split off by the rat, at least in part, and metabolized independently of the remainder of the molecule.