title: Effects of acute renal failure induced by uranyl nitrate on the pharmacokinetics of intravenous theophylline in rats: the role of CYP2E1 induction in 1,3-dimethyluric acid formation.
abstract: In rats with acute renal failure induced by uranyl nitrate, the hepatic microsomal cytochrome P450 (CYP) 2E1 and CYP3A23 increased 2-4- and 4-times, respectively, CYP2C11 decreased to 80% of control, but the levels of CYP1A2 and CYP2B1/2 were not changed. It has been reported that theophylline was metabolized to 1,3-dimethyluric acid by CYP1A2 and CYP2E1 and 1-methylxanthine via CYP1A2, which was metabolized further to 1-methyluric acid via xanthine oxidase in rats. Hence, it was expected that the formation of 1,3-dimethyluric acid would show an increase in rats with renal failure as a result of induction of CYP2E1. The pharmacokinetics of theophylline were compared in control rats and rats with renal failure after intravenous administration of aminophylline, 5 mg kg(-1) as theophylline. In rats with renal failure, the plasma concentrations of theophylline were considerably lower and the resultant total area under the plasma concentration-time curve from time zero to time infinity (AUC(0- infinity )) of theophylline was significantly smaller (2,200 vs 1,550 microg min mL(-1)) compared with control rats. In rats with renal failure, the plasma concentrations of 1,3-dimethyluric acid were considerably higher and the resultant AUC(0-6 h) of 1,3-dimethyluric acid was significantly greater (44.4 vs 456 microg min mL(-1)) compared with control rats. Moreover, the AUC(0-6 h, 1,3-dimethyluric acid)/AUC(0- infinity, theophylline) ratio increased from 2.02% in control rats to 29.4% in rats with renal failure. The in-vitro intrinsic 1,3-dimethyluric acid formation clearance was significantly faster in rats with renal failure (734 vs 529 10(-6) mL min(-1)) compared with control rats using hepatic microsomal fraction. The results led us to conclude that in rats with uranyl nitrate-induced renal failure after the administration of aminophylline, 5 mg kg(-1) as theophylline, there was an increase in the formation of 1,3-dimethyluric acid as a result of an increase in CYP2E1 expression.
authors.affiliation: College of Pharmacy and Research Institute of Pharmaceutical Sciences, Seoul National University, San 56-1, Shinlim-Dong, Kwanak-Gu, Seoul 151-742, Korea.
authors.forename: Su Yeon
authors.initials: SY
authors.lastname: Yu
authors.forename: Hye Chin
authors.initials: HC
authors.lastname: Chung
authors.forename: Eun Jung
authors.initials: EJ
authors.lastname: Kim
authors.forename: So Hee
authors.initials: SH
authors.lastname: Kim
authors.forename: Inchull
authors.initials: I
authors.lastname: Lee
authors.forename: Sang Geon
authors.initials: SG
authors.lastname: Kim
authors.forename: Myung Gull
authors.initials: MG
authors.lastname: Lee
mesh_terms: D058186:Acute Kidney Injury / Q000139:chemically induced / Q000378:metabolism*; D000628:Aminophylline / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D000818:Animals; D019540:Area Under Curve; D002851:Chromatography, High Pressure Liquid; D019392:Cytochrome P-450 CYP2E1 / Q000096:biosynthesis*; D003627:Data Interpretation, Statistical; D004347:Drug Interactions; D004790:Enzyme Induction; D006207:Half-Life; D066298:In Vitro Techniques; D007262:Infusions, Intravenous; D008297:Male; D008862:Microsomes, Liver / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors; D014502:Uranyl Nitrate; D014527:Uric Acid / Q000031:analogs & derivatives* / Q000097:blood / Q000378:metabolism*
chemical_list: D014502:Uranyl Nitrate; D014527:Uric Acid; D000628:Aminophylline; C031274:1,3-dimethyluric acid; D019392:Cytochrome P-450 CYP2E1