title: In vitro study of paraquat effects on malondialdehyde formation in thymus cells.
abstract: The present experiments have shown that paraquat enhanced both O2- production and oxidation of exogenous NADPH in thymus cells by NADPH-dependent enzyme system. The effects of paraquat on malondialdehyde formation were also NADPH-dependent and opposite in the absence and in the presence of ferrous ions: Paraquat inhibited the NADPH-dependent malondialdehyde formation in the absence of Fe2+; it activated this formation in the presence of Fe2+ and had no effect on the nonenzymic Fe2+- and Fe2+-ascorbate-stimulated lipid peroxidation. It is suggested that the activating effect of paraquat on the enzymic NADPH-dependent MDA formation in the presence of Fe2+ is due to the formation of a powerful oxidant product (FeO2)+ or to some Fe2+-paraquat radical complex, acting similarly to the ADP-chelated ferrous ions.
mesh_terms: D000323:Adrenochrome / Q000378:metabolism; D000818:Animals; D005296:Ferrous Compounds / Q000494:pharmacology; D008297:Male; D008314:Malonates / Q000096:biosynthesis*; D008315:Malondialdehyde / Q000096:biosynthesis*; D009249:NADP / Q000378:metabolism; D010084:Oxidation-Reduction; D010269:Paraquat / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013481:Superoxides / Q000378:metabolism; D013950:Thymus Gland / Q000187:drug effects* / Q000378:metabolism
chemical_list: D005296:Ferrous Compounds; D008314:Malonates; D013481:Superoxides; D008315:Malondialdehyde; D009249:NADP; D000323:Adrenochrome; D010269:Paraquat