Role of MRP2 and GSH in intrahepatic cycling of toxins
| Autor: | Roelof Ottenhoff, R P Oude Elferink, D. R. de Waart, Christoph G. Dietrich |
|---|---|
| Přispěvatelé: | Other departments |
| Jazyk: | angličtina |
| Rok vydání: | 2001 |
| Předmět: |
Male
ATP Binding Cassette Transporter Subfamily B Arsenites Toxicology Cell Line chemistry.chemical_compound Dogs Cholestasis Transduction Genetic medicine Animals Bile Secretion Rats Wistar Cells Cultured Arsenite Multidrug resistance-associated protein 2 Hepatobiliary disease Membrane Transport Proteins Glutathione medicine.disease Molecular biology Multidrug Resistance-Associated Protein 2 Rats medicine.anatomical_structure 1-Naphthylisothiocyanate Liver chemistry Biochemistry Hepatocyte Toxicity ATP-Binding Cassette Transporters Multidrug Resistance-Associated Proteins Carrier Proteins |
| Zdroj: | Toxicology, 167(1), 73-81. Elsevier Ireland Ltd |
| ISSN: | 0300-483X |
| DOI: | 10.1016/s0300-483x(01)00459-0 |
| Popis: | MRP2 is a canalicular transporter in hepatocytes mediating the transport of a wide spectrum of amphipathic compounds. This includes organic anions but also compounds complexed with GSH as, e.g. alpha-naphthylisothiocyanate (ANIT) and arsenite. These reversible complexes may fall apart in bile after MRP2-mediated transport, which induces high concentrations of the toxic compound in the biliary tree. To further investigate the role of MRP2 in transport and toxicity of both compounds, we conducted experiments in transduced polarized epithelial cells and in vivo, using the Mrp2-deficient TR(-) rat as a model. Our results show, that in MRP2-transduced MDCK II cells both compounds induce disproportionally strong apical GSH secretion. This induction of GSH secretion was not observed in the parent cells lacking MRP2 expression. This indicated that after transport via MRP2 both complexes released GSH upon which the compound could re-enter the cells. The resulting cycling of both toxins led to concentration dependent GSH depletion of the cells. To further test our hypothesis we administered arsenite (12.5 micromol absolute i.v.) to Wistar and Mrp2-deficient TR(-) rats and collected bile. While both arsenite and GSH secretion were absent in TR(-) rats, the total secretion of arsenite into Wistar bile (2.91 micromol) was accompanied by a excess secretion of 24 micromol GSH, indicating that arsenite undergoes multiple cycles of GSH complexation. We also administered ANIT to both animal models and could show that TR(-) rats are protected from ANIT induced cholestasis. This indicates that Mrp2-mediated biliary secretion of GS-ANIT is a prerequisite for development of cholestasis in rats. We hypothesize that the toxic parent compound ANIT is regenerated in the biliary tree where it can exert its toxic properties on bile duct epithelial cells. |
| Databáze: | OpenAIRE |
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