Metabolic activation of 2-methylfuran by rat microsomal systems

Ravindranath, Vijayalakshmi ; Boyd, Michael R. (1985) Metabolic activation of 2-methylfuran by rat microsomal systems Toxicology and Applied Pharmacology, 78 (3). pp. 370-376. ISSN 0041-008X

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Official URL: http://linkinghub.elsevier.com/retrieve/pii/004100...

Related URL: http://dx.doi.org/10.1016/0041-008X(85)90242-X

Abstract

2-Methylfuran (2-MF), a constituent of cigarette smoke and coffee, causes necrosis of liver, lungs, and kidneys in rodents. 2-MF is metabolically activated by mixed-function oxidases to acetylacrolein, a reactive metabolite that binds covalently to microsomal protein. The hepatic microsomal metabolism of 2-MF to reactive metabolite required the presence of NADPH and oxygen and was dependent on incubation time and substrate concentration. The microsomal metabolism of 2-MF was inducible by pretreatment of rats with phenobarbital and was inhibited by piperonyl butoxide and N-octyl imidazole, which indicates that the metabolism of 2-MF may be mediated by cytochrome P-450. Acetylcrolein was a potent inhibitor of mixed-function oxidase and completely inhibited the microsomal metabolism of 2-MF, indicating that 2-MF is a suicide substrate for the enzyme. The sulfhydryl nucleophile cysteine was a better trapping agent of the reactive metabolite of 2-MF than N-acetylcysteine or glutathione. Lysine decreased the covalent binding of 2-MF metabolites, presumably by reacting with the aldehyde group of acetylacrolein. In addition, in the presence of NADPH, 2-MF was bioactivated by both pulmonary and renal cortical microsomes to reactive metabolites that were covalently bound to microsomal proteins.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
ID Code:40675
Deposited On:24 May 2011 13:21
Last Modified:24 May 2011 13:21

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