title: Hormonal regulation of heme oxygenase induction in avian hepatocyte culture.
abstract: The effects of various hormones were examined on the induction of heme oxygenase in monolayer cultures in chick embryo hepatocytes maintained in a chemically defined medium. Addition of insulin to the cultured cells markedly suppressed the activity of basal as well as Co2+-induced heme oxygenase. Treatment of cells with hydrocortisone also suppressed the basal enzyme activity, while the Co2+-induced enzyme activity was enhanced slightly. In contrast, triiodothyronine addition to the culture caused a slight increase of both uninduced and induced levels of the enzyme. This stimulatory effect of triiodothyronine was enhanced significantly by prolonged incubation of cells (48-96 hr) in the serum-free medium. These findings indicate that heme oxygenase synthesis can be substantially altered by changing the hormonal environment of the hepatocytes. Furthermore, the induction of heme oxygenase by Co2+ was inhibited by glucagon, dibutyryl cAMP and theophylline in a dose-dependent manner, suggesting that the enzyme induction may also be controlled by changes in cAMP levels.
authors.forename: M K
authors.initials: MK
authors.lastname: Sardana
authors.forename: S
authors.initials: S
authors.lastname: Sassa
authors.forename: A
authors.initials: A
authors.lastname: Kappas
mesh_terms: D000624:5-Aminolevulinate Synthetase / Q000096:biosynthesis; D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D002478:Cells, Cultured; D002642:Chick Embryo; D003035:Cobalt / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004790:Enzyme Induction / Q000187:drug effects; D004837:Epinephrine / Q000494:pharmacology; D005934:Glucagon / Q000494:pharmacology; D006419:Heme Oxygenase (Decyclizing) / Q000096:biosynthesis*; D006728:Hormones / Q000494:pharmacology*; D006854:Hydrocortisone / Q000494:pharmacology; D007328:Insulin / Q000494:pharmacology; D007545:Isoproterenol / Q000494:pharmacology; D008099:Liver / Q000201:enzymology*; D006899:Mixed Function Oxygenases / Q000096:biosynthesis*; D013806:Theophylline / Q000494:pharmacology; D014284:Triiodothyronine / Q000494:pharmacology
chemical_list: D006728:Hormones; D007328:Insulin; D014284:Triiodothyronine; D003035:Cobalt; D003994:Bucladesine; D005934:Glucagon; D013806:Theophylline; D006899:Mixed Function Oxygenases; D006419:Heme Oxygenase (Decyclizing); D000624:5-Aminolevulinate Synthetase; D007545:Isoproterenol; D006854:Hydrocortisone; D004837:Epinephrine