title: The role of 5-aminolaevulinate synthase, haem oxygenase and ligand formation in the mechanism of maintenance of cytochrome P-450 concentration in hepatocyte culture.
abstract: The present work shows that the ability of pyridines e.g. metyrapone, to maintain the cytochrome P-450 concentration in cultured hepatocytes is not due to their ability to alter the 5-aminolaevulinate synthase and haem oxygenase activities of the hepatocytes. Since ligands such as metyrapone will prevent the cobalt-mediated loss of hepatic cytochrome P-450 in rats, the hypothesis that ligand formation is the mechanism of maintenance of the cytochrome in hepatocyte culture was tested. The observation that non-pyridine ligands will maintain the cytochrome P-450 concentration supports this hypothesis.
mesh_terms: D000624:5-Aminolevulinate Synthetase / Q000378:metabolism*; D000818:Animals; D002478:Cells, Cultured; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D006419:Heme Oxygenase (Decyclizing) / Q000378:metabolism*; D007093:Imidazoles / Q000494:pharmacology; D008024:Ligands; D008099:Liver / Q000166:cytology / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D008797:Metyrapone / Q000494:pharmacology; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D011725:Pyridines / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D007093:Imidazoles; D008024:Ligands; D011725:Pyridines; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases; D006419:Heme Oxygenase (Decyclizing); D000624:5-Aminolevulinate Synthetase; D008797:Metyrapone