title: Quantitative studies of the metabolism of furazolidone by rat liver microsomes.
abstract: The nitrofuran, furazolidone, is metabolized by rat liver microsomes under both aerobic and anaerobic conditions, the rates for microsomes from 3-methylcholanthrene-induced male rats being 3.52 and 4.26 nmol/mg protein/min, respectively. The two major metabolites formed are the well-known 3-(4-cyano-2-oxobutylideneamino)-2-oxazolidone, and 2,3-dihydro-3-cyanomethyl-2-hydroxy-5-nitro-1alpha,2-di-(2-oxo-oxazolidin-3-yl)iminomethylfuro[2,3-b]furan (accounting for 16.6 and 16.4% of total extractable radioactivity, respectively). Cytochrome P-450 is not involved in the conversion of furazolidone, which was converted by rat liver microsomes to products identical to those obtained upon incubation with purified NADPH-cytochrome P-450 reductase, which is a microsomal reductase. During metabolism, a considerable amount of material (2-3% of total metabolites) became covalently bound to microsomal protein. This covalent binding could be inhibited by addition of glutathione, which also resulted in an almost complete shift from non-polar to water-soluble metabolites. No interaction of furazolidone with added calf thymus DNA was detected.
authors.affiliation: State Institute for Quality Control of Agricultural Products, Toxicology Section, Bornsesteeg 45, 6708 PD Wageningen, The Netherlands.
authors.forename: L H
authors.initials: LH
authors.lastname: Vroomen
authors.forename: B
authors.initials: B
authors.lastname: van Ommen
authors.forename: P J
authors.initials: PJ
authors.lastname: van Bladeren