title: Hepatic drug metabolism and haem biosynthesis in lead-poisoned rats.
abstract: 1 Pretreatment of rats with intraperitoneal injections of lead was shown to result in a depression of the microsomal mixed function oxidase system, as assessed by a decrease in hepatic microsomal P-450 and b5 content and by a decrease in the activity of the enzymes aniline hydroxylase and aminopyrine demethylase. Lead had a more marked effect on cytochrome P-450 than b5. 2 The activity of the rate-limiting enzyme of haem biosynthesis, delta-aminolaevulinic acid synthase, was inversely correlated with the microsomal cytochrome P-450 content. 3 The activity of the haem biosynthetic enzymes delta-aminolaevulinic acid dehydratase, coproporphyrinogen oxidase and ferrochelatase were decreased by increasing lead pretreatment. 4 The activity of the haem catabolic enzyme, haem oxygenase, was increased by lead pretreatment.
mesh_terms: D000624:5-Aminolevulinate Synthetase / Q000378:metabolism; D000818:Animals; D006418:Heme / Q000096:biosynthesis*; D066298:In Vitro Techniques; D007855:Lead Poisoning / Q000378:metabolism*; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism; D006899:Mixed Function Oxygenases / Q000378:metabolism; D004364:Pharmaceutical Preparations / Q000378:metabolism*; D051381:Rats
chemical_list: D004364:Pharmaceutical Preparations; D006418:Heme; D006899:Mixed Function Oxygenases; D000624:5-Aminolevulinate Synthetase