title: Studies on in vitro antipyrine metabolism by 13C,15N double labeled method.
abstract: The capacities of forms of cytochrome P-450 to oxidize antipyrine were compared. An isotope dilution gas chromatography/mass spectrometry/selected ion monitoring assay was developed to quantify the three main metabolites, norantipyrine, 3-hydroxymethylantipyrine and 4-hydroxyantipyrine. 13C,15N-Double labeled antipyrine was used as a substrate and the metabolites were analyzed as their trimethylsilyl derivatives. Among forms of cytochrome P-450 examined, a male-specific form of P-450, namely P-450-male, showed higher activity to form all the three metabolites. The other forms were responsible only for the formation of norantipyrine and 4-hydroxyantipyrine. The activities of liver microsomes from untreated male and female rats and rats treated with phenobarbital, 3-methylcholanthrene or polychlorinated biphenyl were expressed dependent on the activities of forms of cytochrome P-450 examined.
authors.forename: A
authors.initials: A
authors.lastname: Nakagawa
authors.forename: K
authors.initials: K
authors.lastname: Nakamura
authors.forename: K
authors.initials: K
authors.lastname: Maeda
authors.forename: T
authors.initials: T
authors.lastname: Kamataki
authors.forename: R
authors.initials: R
authors.lastname: Kato
mesh_terms: D000818:Animals; D000983:Antipyrine / Q000378:metabolism*; D002247:Carbon Isotopes; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D005260:Female; D008401:Gas Chromatography-Mass Spectrometry; D007201:Indicator Dilution Techniques; D007700:Kinetics; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology; D009587:Nitrogen Isotopes; D051381:Rats; D011919:Rats, Inbred Strains
chemical_list: D002247:Carbon Isotopes; D009587:Nitrogen Isotopes; D003577:Cytochrome P-450 Enzyme System; D000983:Antipyrine