title: Faster clearance of omeprazole in mutant Nagase analbuminemic rats: possible roles of increased protein expression of hepatic CYP1A2 and lower plasma protein binding.
abstract: It is well known that there are various changes in the expression of hepatic and intestinal CYPs in mutant Nagase analbuminemic rats (NARs). It has been reported that the protein expression of hepatic CYP1A2 was increased, whereas that of hepatic CYP3A1 was not altered, and it was also found that the protein expression of the intestinal CYP1A subfamily significantly increased in NARs from our other study. In addition, in this study additional information about CYP changes in NARs was obtained; the protein expression of the hepatic CYP2D subfamily was not altered, but that of the intestinal CYP3A subfamily increased in NARs. Because omeprazole is metabolized via hepatic CYP1A1/2, 2D1, 3A1/2 in rats, it could be expected that the pharmacokinetics of omeprazole would be altered in NARs. After intravenous administration of omeprazole to NARs, the Cl(nr) was significantly faster than in the controls (110 versus 46.6 ml/min/kg), and this could be due to an increase in hepatic metabolism caused by a greater hepatic CYP1A2 level in addition to greater free fractions of the drug in NARs. After oral administration of omeprazole to NARs, the AUC was also significantly smaller (80.1% decrease) and F was decreased in NARs. This could be primarily due to increased hepatic and intestinal metabolism caused by greater hepatic CYP1A2 and intestinal CYP1A and 3A levels. In particular, the smaller F could mainly result from greater hepatic and intestinal first-pass effect in NARs than in the controls.
authors.affiliation: College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, Seoul, Republic of Korea.
authors.forename: Dae Y
authors.initials: DY
authors.lastname: Lee
authors.forename: Young S
authors.initials: YS
authors.lastname: Jung
authors.forename: Young C
authors.initials: YC
authors.lastname: Kim
authors.forename: Sung Y
authors.initials: SY
authors.lastname: Kim
authors.forename: Myung G
authors.initials: MG
authors.lastname: Lee
mesh_terms: D000118:Acetylglucosaminidase / Q000235:genetics / Q000378:metabolism*; D000284:Administration, Oral; D000818:Animals; D019540:Area Under Curve; D019388:Cytochrome P-450 CYP1A2 / Q000378:metabolism*; D051544:Cytochrome P-450 CYP3A / Q000378:metabolism; D003580:Cytochromes; D007262:Infusions, Intravenous; D007422:Intestines / Q000201:enzymology; D007527:Isoenzymes; D008099:Liver / Q000201:enzymology*; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology; D009154:Mutation; D009853:Omeprazole / Q000008:administration & dosage / Q000493:pharmacokinetics*; D011485:Protein Binding; D054328:Proton Pump Inhibitors / Q000008:administration & dosage / Q000493:pharmacokinetics*; D051381:Rats; D011922:Rats, Mutant Strains; D017207:Rats, Sprague-Dawley; D015854:Up-Regulation
chemical_list: D003580:Cytochromes; D007527:Isoenzymes; D054328:Proton Pump Inhibitors; C017170:Cyp1a2 protein, rat; D019388:Cytochrome P-450 CYP1A2; D051544:Cytochrome P-450 CYP3A; D000118:Acetylglucosaminidase; D009853:Omeprazole