title: Prolonged induction of hepatic haem oxygenase and decreases in cytochrome P-450 content by organotin compounds.
abstract: The administration of organotin compounds to rats in single doses causes a significant and prolonged induction of haem oxygenase and a sustained decrease in haemoprotein content in the liver. The extent of induction of hepatic haem oxygenase varied between 3 and 5-fold at 72h after a single injection of water-insoluble organotins of differing structure. The alterations in haem metabolism produced by tricyclohexyltin hydroxide were studied in detail. The effects were dose-dependent, with doses as low as 3.75 mg/kg body wt. resulting in significant induction of haem oxygenase and a decrease in cytochrome P-450 and cytochrome b5 contents at 72h in the liver. The effects with time of a single dose of tricyclohexyltin on various parameters of liver haem metabolism were also examined. The organotin produced a substantial and very prolonged induction of haem oxygenase accompanied by a steady decline in cytochrome P-450 content for periods up to 8 days. The long duration of action of these organotins with respect to induction of haem oxygenase and depletion of cellular haemoprotein content provides a highly sensitive metabolic system with which to define further the toxic potential of organometals as well as to study the adaptive responses in liver to long-term perturbations of haem metabolism by foreign chemicals.
mesh_terms: D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D003580:Cytochromes / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004790:Enzyme Induction / Q000187:drug effects; D006419:Heme Oxygenase (Decyclizing) / Q000096:biosynthesis*; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology*; D006899:Mixed Function Oxygenases / Q000096:biosynthesis*; D009947:Organotin Compounds / Q000494:pharmacology*; D051381:Rats; D013997:Time Factors
chemical_list: D003580:Cytochromes; D009947:Organotin Compounds; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D006419:Heme Oxygenase (Decyclizing)