Document Detail


Metabolism of antipyrine in vivo in two rat models of liver cirrhosis. Its relationship to intrinsic clearance in vitro and microsomal membrane lipid composition.
MedLine Citation:
PMID:  8216358     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Antipyrine metabolism depends on at least three isoenzymes of cytochrome P450 forming the main metabolites 3-OH-, 4-OH- and norantipyrine. We investigated to what extent antipyrine clearance and metabolite formation are impaired in two models of liver cirrhosis in the rat, namely micronodular cirrhosis induced by chronic exposure to phenobarbital/CCl4 and biliary cirrhosis induced by bile duct ligation. Salivary antipyrine clearance was decreased to a similar extent in cirrhosis induced by CCl4 and bile duct ligation (-35%). Clearance for production of 3-OH-antipyrine was decreased in both models, while 4-hydroxylation was maintained. Metabolic clearance of both 3-OH-antipyrine and 4-OH-antipyrine in vivo correlated with their clearance in vitro (r = 0.658 and r = 0.583) but not with that of norantipyrine. The microsomal cholesterol content was increased by 16% and 90% in CCl4 and bile duct-ligated cirrhotic rats (P < 0.001), respectively. Membrane fluidity, expressed as the ratio of phospholipids to cholesterol, correlated with the in vivo clearance for production of norantipyrine (r = 0.841) but not of 3-OH- or 4-OH-antipyrine, while clearance in vitro was not related to altered lipid composition. Our results demonstrate that the cytochrome P450 isoenzymes responsible for the different pathways of antipyrine metabolism are affected to different extents by cirrhosis. Alterations in intrinsic clearance explain only part of the loss of hepatocellular function. Altered lipid composition contributes to this loss of function but other factors, among them loss of hepatocytes and changes in microcirculation, could be more important determinants of the decrease in xenobiotic metabolism in cirrhosis.
Authors:
J T Buters; T Zysset; J Reichen
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Biochemical pharmacology     Volume:  46     ISSN:  0006-2952     ISO Abbreviation:  Biochem. Pharmacol.     Publication Date:  1993 Sep 
Date Detail:
Created Date:  1993-11-01     Completed Date:  1993-11-01     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0101032     Medline TA:  Biochem Pharmacol     Country:  ENGLAND    
Other Details:
Languages:  eng     Pagination:  983-91     Citation Subset:  IM    
Affiliation:
Department of Clinical Pharmacology, University of Berne, Switzerland.
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MeSH Terms
Descriptor/Qualifier:
Animals
Antipyrine / metabolism*,  pharmacokinetics,  urine
Bile Acids and Salts / blood
Breath Tests
Carbon Tetrachloride
Lipids / analysis
Liver Cirrhosis, Biliary / metabolism*,  pathology
Liver Cirrhosis, Experimental / metabolism*,  pathology
Male
Membrane Fluidity
Microsomes, Liver / metabolism,  ultrastructure
Models, Biological
Organ Size
Phenobarbital
Rats
Rats, Sprague-Dawley
Saliva / metabolism
Chemical
Reg. No./Substance:
0/Bile Acids and Salts; 0/Lipids; 50-06-6/Phenobarbital; 56-23-5/Carbon Tetrachloride; 60-80-0/Antipyrine

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