title: Comparison of the photochemical and enzymic generation of excited states of oxygen on the induction of benzo(alpha)pyrene mono-oxygenase in liver cell cultures.
abstract: The photochemical generation of excited states of oxygen such as the superoxide ion(O-2) and singlet oxygen (1o2) by the mild illumination of culture medium containing riboflavin induces benzo(alpha)pyrene mono-oxygenase in 3 different cell lines derived from rat liver. Similar rates of O-2 generation can be produced by the action of xanthine oxidase on xanthine yet this system does not induce the mono-oxygenase. This result confirms that the mono-oxygenase induction is not mediated by O-2 is not mediated by O-2 and that 1O2 is the most likely candidate for stimulating the mono-oxygenase activity.
mesh_terms: D000818:Animals; D001189:Aryl Hydrocarbon Hydroxylases / Q000096:biosynthesis*; D001579:Benzopyrene Hydroxylase / Q000096:biosynthesis*; D002460:Cell Line; D002478:Cells, Cultured; D004790:Enzyme Induction / Q000187:drug effects; D005609:Free Radicals; D007700:Kinetics; D008027:Light; D008099:Liver / Q000187:drug effects / Q000201:enzymology*; D010100:Oxygen / Q000494:pharmacology*; D051381:Rats; D012256:Riboflavin / Q000494:pharmacology; D013481:Superoxides / Q000494:pharmacology*; D014969:Xanthine Oxidase / Q000378:metabolism
chemical_list: D005609:Free Radicals; D013481:Superoxides; D001579:Benzopyrene Hydroxylase; D001189:Aryl Hydrocarbon Hydroxylases; D014969:Xanthine Oxidase; D010100:Oxygen; D012256:Riboflavin