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Pharmaceutisch Weekblad

, Volume 14, Issue 3, pp 127–131 | Cite as

Effects of valproate on xenobiotic biotransformation in rat liver

In vivo andin vitro experiments
  • V. Rogiers
  • A. Callaerts
  • A. Vercruysse
  • M. Akrawi
  • E. Shephard
  • I. Phillips
Recent Developments on Valproate and its Metabolites

Abstract

Male Wistar rats werein vivo exposed for 2 weeks to 100 μg/ml sodium valproate by subcutaneous implantation of osmotic pumps and hepatocytes were isolated. As anin vitro model co-cultures of rat hepatocytes with epithelial cells were daily treated with valproate (25, 50, 100, 200μg/ml) for 2 weeks. In both models the cytochrome P-450 content and the enzymatic activities of 7-ethoxycoumarinO-deethylase, aldrin epoxidase and glutathioneS-transferase were determined in valproate-treated hepatocytes, in controls and in phenobarbital-induced cells. It appeared that in both systems the cytochrome P-450 content and the 7-ethoxycoumarinO-deethylase activity increased significantly after valproate treatment. On the other hand, the activities of aldrin epoxidase and glutathioneS-transferase decreased. A cDNA probe, encoding rat P450IIB2 was used to determine whether mRNAs encoding the P450IIB subfamily were induced by valproate. It became clear that the inducing effect of valproate was even more pronouncedin vitro thanin vivo.

Keywords

Aldrin epoxidase 7-AlkoxycoumarinO-dealkylase Biotransformation Cytochrome P-450 Enzyme induction Glutathione transferases Hepatocytes Valproic acid 

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Copyright information

© Royal Dutch Association for Advancement of Pharmacy 1992

Authors and Affiliations

  • V. Rogiers
    • 1
  • A. Callaerts
    • 1
  • A. Vercruysse
    • 1
  • M. Akrawi
    • 2
  • E. Shephard
    • 2
  • I. Phillips
    • 3
  1. 1.Department of ToxicologyFree University BrusselsBrusselsBelgium
  2. 2.Department of Biochemistry and Molecular BiologyUniversity College LondonLondonUK
  3. 3.Department of Biochemistry, Queen Mary and Westfield CollegeUniversity of LondonLondonUK

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