title: Dietary antioxidant effects on the hepatic mixed-function oxidase system of rainbow trout (Salmo Gairdneri).
abstract: Rainbow trout (Salmo gairdneri) were fed a control diet with or without an antioxidant--3,5-di-tert-butyl-4-hydroxytoluene (BHT), 2(3)-tert-butyl-4-hydroxyanisole (BHA), mono-tert-butylhydroquinone (TBHQ) or ethoxyquin (EQ)--at a level of 5.56 mmol in 100 g oil/kg diet for 6 wk. The treated trout had reduced liver weight/body weight ratios. In comparison with trout fed control diet, microsomal protein content was lowered by 13% in TBQH-fed trout and elevated by 28% in EQ-fed trout, cytochrome P-450 content was 21% lower in BHA- and TBHQ-fed and 18% lower in EQ-fed trout and cytochrome b5 content was 46% lower in EQ-fed trout. Activities of benzo[a]pyrene hydroxylase, epoxide hydratase and ethoxycoumarin-O-deethylase were, respectively, 3.2-4.8, 1.2-1.7 and 1.3-5.5 times higher in antioxidant-fed trout. NADPH-cytochrome c reductase was elevated 1.2-1.3 times over the control value with dietary BHA, TBHQ and BHT, but was lowered with EQ. p-Nitroanisole-O-demethylase activity was completely suppressed in antioxidant-fed trout. The content of post-mitochondrial acid-soluble sulphydryl groups was 42% lower in BHA- and BHT-fed trout. Alterations in the enzyme activities of the mixed-function oxidase system, changes in the ethyl isocyanide binding ratio and decreases in cytochrome P-450 content suggest that dietary antioxidants could alter carcinogen activation and/or detoxification mechanisms in the hepatic microsomes of rainbow trout.
mesh_terms: D015660:7-Alkoxycoumarin O-Dealkylase; D000348:Aflatoxins / Q000378:metabolism; D000818:Animals; D000975:Antioxidants; D001580:Benzopyrenes / Q000378:metabolism; D002083:Butylated Hydroxyanisole / Q000494:pharmacology; D002084:Butylated Hydroxytoluene / Q000494:pharmacology; D004790:Enzyme Induction; D004851:Epoxide Hydrolases / Q000096:biosynthesis; D008099:Liver / Q000201:enzymology*; D006899:Mixed Function Oxygenases / Q000096:biosynthesis*; D010088:Oxidoreductases / Q000096:biosynthesis*; D010105:Oxygenases / Q000096:biosynthesis; D012487:Salmonidae / Q000378:metabolism*; D014337:Trout / Q000378:metabolism*
chemical_list: D000348:Aflatoxins; D000975:Antioxidants; D001580:Benzopyrenes; D002084:Butylated Hydroxytoluene; D002083:Butylated Hydroxyanisole; D006899:Mixed Function Oxygenases; D010088:Oxidoreductases; D010105:Oxygenases; D015660:7-Alkoxycoumarin O-Dealkylase; D004851:Epoxide Hydrolases