Comparative induction of CYP1A1 expression by pyridine and its metabolites
| Autor: | Jacqueline Fung, Allan B. Okey, John V. Giannone, Michael M. Iba |
|---|---|
| Rok vydání: | 2000 |
| Předmět: |
Male
Pyridines Pyridones Blotting Western Biophysics Kidney Biochemistry Cell Line Rats Sprague-Dawley chemistry.chemical_compound Cytosol In vivo Microsomes Pyridine Cytochrome P-450 CYP1A1 Animals Electrophoretic mobility shift assay Rats Long-Evans Tissue Distribution Northern blot RNA Messenger Molecular Biology Lung chemistry.chemical_classification biology respiratory system Aryl hydrocarbon receptor Blotting Northern Rats Blot Enzyme chemistry Liver Receptors Aryl Hydrocarbon Enzyme Induction biology.protein Microsomes Liver Protein Binding |
| Zdroj: | Archives of biochemistry and biophysics. 378(2) |
| ISSN: | 0003-9861 |
| Popis: | We compared pyridine and five of its metabolites in terms of (i) in vivo induction of CYP1A1 expression in the lung, kidney, and liver in the rat and (ii) in vitro binding to, and activation of, the aryl hydrocarbon receptor (AhR) in cytosol from rat liver or Hepa1c1c7 cells. Following a single 2.5 mmol/kg ip dose of either pyridine, 2-hydroxpyridine, 3-hydroxypyridine, 4-hydroxypyridine, N-methylpyridinium, or pyridine N-oxide, CYP1A1 activity (ethoxyresorufin O-deethylase), protein level (as determined by Western blotting), and mRNA level (as determined by Northern blotting) were induced by pyridine, N-methylpyridinium, and pyridine N-oxide in the lung, kidney, and liver. The induction by N-methylpyridinium or pyridine N-oxide was comparable to or greater than that by pyridine in some tissues. 2-Hydroxypyridine and 3-hydroxypyridine caused tissue-specific induction or repression of CYP1A1, whereas 4-hydroxypyridine had no effect on the expression of the enzyme. Pyridine and its metabolites elicited weak activation of the aryl hydrocarbon receptor in a gel retardation assay in cytosol from rat liver but not Hepa 1c1c7 cells. However, the receptor activation did not parallel the in vivo CYP1A1 induction by the pyridine compounds, none of which inhibited binding of [3H]2,3,7,8-tetrachlorodibenzo-p-dioxin to AhR in a competitive assay in rat liver cytosol. The findings are consistent with a role of pyridine metabolites in CYP1A1 induction by pyridine but do not clearly identify the role of aryl hydrocarbon receptor in the induction mechanism. |
| Databáze: | OpenAIRE |
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