Využití molekulárně biologických in vitro metod pro interpretaci mechanizmů vybraných lékových interakcí warfarinu
Xenobiotics are metabolized by hepatic biotransformation enzymes of cytochrome P450. Drug-drug interactions, where one substance increases the activity of biotransformation enzymes involved in the metabolism of other drug and accelerate its elimination, often occure in xenobiotics metabolism. The pr...
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| Format: | Dissertation |
| Language: | Czech |
| Published: |
2009
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| Online Access: | http://www.nusl.cz/ntk/nusl-279062 |
| Summary: | Xenobiotics are metabolized by hepatic biotransformation enzymes of cytochrome P450. Drug-drug interactions, where one substance increases the activity of biotransformation enzymes involved in the metabolism of other drug and accelerate its elimination, often occure in xenobiotics metabolism. The pregnane X receptor is a ligand-activated nuclear receptor, which plays central role in induction of numerous genes involved in the phase I. and II. of biotransformation including the most important hepatic enzyme CYP3A4. The aim of the diploma thesis was to examine interaction of warfarin and its enantiomers with PXR in terms of transactivation of CYP3A4 gene in hepatoma cell line HepG2 or in primary human hepatocytes. The cytotoxicity of warfarin was tested on cell line HepG2 using the MTT assay. Cytotoxic activity of warfarin didn't become evident in tested concentrations. Using the methods gene reporter assay and two-hybrid assay, we found that R-warfarin induces CYP3A4 gene expression through nuclear receptor PXR. Using the method RT-PCR, we observed induction effect of warfarin and its enantiomers on the CYP3A4 gene expression in isolated hepatocytes of two donors. I can conclude that activation of PXR by warfarin may cause pharmacokinetic drug-drug interactions of pharmaceuticals metabolized by CYP3A4. |
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