title: Generation of low-level chemiluminescence during the metabolism of 1-naphthol by rat liver microsomes.
abstract: The metabolism of 1-naphthol in rat liver microsomal fractions supplemented with NADPH is accompanied by low-level chemiluminescence which reflects the formation of molecular excited states. Photoemission consists of two phases which both are dependent on microsomal protein and 1-naphthol concentration. The involvement of cytochrome P-450 in the microsomal metabolism of 1-naphthol was indicated by an inhibition of chemiluminescence by aminopyrine or metyrapone. Oxygen is required for light emission. Whereas phase I is hardly influenced by superoxide dismutase, phase II is suppressed. Chemiluminescence was not associated with malondialdehyde accumulation, in contrast to NADPH-dependent lipid peroxidation in microsomal fractions in the absence of 1-naphthol. Phase I of chemiluminescence appears to directly reflect cytochrome P-450-dependent hydroxylation, and phase II is attributed to redox cycling of products arising from these reactions, e.g. the 1,4- and/or 1,2-naphthoquinones as oxidation products of the corresponding dihydroxynaphthalenes.
mesh_terms: D000632:Aminopyrine / Q000494:pharmacology; D000818:Animals; D001728:Dicumarol / Q000494:pharmacology; D066298:In Vitro Techniques; D008163:Luminescent Measurements; D008315:Malondialdehyde / Q000378:metabolism; D008797:Metyrapone / Q000494:pharmacology; D008862:Microsomes, Liver / Q000378:metabolism*; D009284:Naphthols / Q000378:metabolism*; D010101:Oxygen Consumption; D011808:Quinone Reductases / Q000037:antagonists & inhibitors; D051381:Rats
chemical_list: D009284:Naphthols; D000632:Aminopyrine; C029350:1-naphthol; D008315:Malondialdehyde; D001728:Dicumarol; D011808:Quinone Reductases; D008797:Metyrapone