| Autor: |
Su, Gloria M., Sefton, Rachel M., Murray, Michael |
| Zdroj: |
The Journal of Pharmacology and Experimental Therapeutics; December 1999, Vol. 291 Issue: 3 p953-959, 7p |
| Abstrakt: |
Microvesicular steatosis is an important component of the overall pathogenesis of drug-mediated liver injury. Although mitochondrial damage has a role in the development of microvesicular steatosis, the consequences of fatty change for hepatic gene function are unclear. The present study was undertaken to evaluate hepatic cytochrome P-450 (CYP) function in a rat model of microvesicular steatosis produced by the intake of diets containing 1% orotic acid (OA) that were administered for 5, 10, or 21 days. Hepatic triglyceride levels were increased to 3-fold of control after 5 days and were elevated further at 10 and 21 days. Cholesterol and phospholipid contents were increased after 10 and 21 days but not by 5 days of feeding. Microsomal androst-4-ene-3,17-dione hydroxylation activities mediated by CYP2C11 (16α-hydroxylation) and CYP3A2 (6β-hydroxylation) were decreased in liver from OA-fed rats for only 5 days, whereas CYP2A1/2-mediated steroid 7α-hydroxylation was decreased after 10 days; these observations were complemented by immunoblot analysis that demonstrated the impaired expression of the corresponding CYP proteins. CYP2C11 mRNA, the major CYP in male rat liver, was down-regulated in steatotic liver to 52 ± 4% of control. Thus, microvesicular steatosis induced by short-term intake of OA-containing diets is histologically similar to that produced by hepatotoxic drugs and produces the rapid down-regulation of constitutive CYPs in rat liver. Analogous processes of lipid deposition in human liver after drug- or disease-related injury could precipitate adverse effects during subsequent drug therapy. |
| Databáze: |
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