Document Detail


Alterations in the renal excretion of valproate and its metabolites after chronic treatment.
MedLine Citation:
PMID:  1985825     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Urinary excretion of valproate (VPA, administered as its sodium salt) and its various metabolites was studied in rats before and after 6 weeks of chronic treatment with intraperitoneal (i.p.) injection of 200 mg/kg VPA three times daily. Urinary excretion was determined after i.p. injection of a single dose of 200 mg/kg VPA, to which [14C]labeled VPA had been added to yield a dose of 1 microCi/kg body weight. Unlabeled VPA and metabolites were determined in urine by gas chromatography-mass spectrometry (GC-MS). After injection of a single dose of VPA before onset of chronic treatment, approximately 40-50% of the dose administered was excreted in the urine within 24 h, mainly in the form of conjugated VPA and omega-oxidation products, i.e., 5-hydroxy-VPA and 2-propyl-glutaric acid. After chronic treatment, urinary excretion of total radioactivity increased approximately 75% as compared with activity before chronic treatment, demonstrating a marked increase in elimination rate of VPA during prolonged administration. Determination of VPA and metabolites in urine by GC-MS indicated that this enhanced elimination resulted mainly from increases in glucuronidation and beta-oxidation of VPA, whereas omega-oxidation was apparently not altered or was even reduced. The data strongly indicate that at least in rats VPA produces induction of its own metabolism during prolonged treatment.
Authors:
J E Fisher; H Nau; W Löscher
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Epilepsia     Volume:  32     ISSN:  0013-9580     ISO Abbreviation:  Epilepsia     Publication Date:    1991 Jan-Feb
Date Detail:
Created Date:  1991-02-11     Completed Date:  1991-02-11     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  2983306R     Medline TA:  Epilepsia     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  146-50     Citation Subset:  IM    
Affiliation:
Institute of Toxicology and Embryopharmacology, Free University of Berlin, F.R.G.
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MeSH Terms
Descriptor/Qualifier:
Animals
Arylsulfatases / metabolism
Biotransformation
Carbon Radioisotopes
Enzyme Induction
Female
Gas Chromatography-Mass Spectrometry
Glucuronidase / metabolism
Injections, Intraperitoneal
Rats
Rats, Inbred Strains
Valproic Acid / administration & dosage,  metabolism,  urine*
Chemical
Reg. No./Substance:
0/Carbon Radioisotopes; 99-66-1/Valproic Acid; EC 3.1.6.1/Arylsulfatases; EC 3.2.1.31/Glucuronidase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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