Abstract
The metabolism of radiolabeled monochloronitrobenzene isomers was compared in isolated hepatocytes and hepatic subcellular fractions from male Fischer-344 rats. 2-Chloronitrobenezene was converted by isolated hepatocytes to 2-chloroaniline, 2-chloroaniline-N-glucuronide, and S-(2-nitrophenyl)glutathione in approximately equal quantities (13-19% of the added substrate in 90 min). The major metabolite formed from 3-chloronitrobenzene by isolated hepatocytes was 3-chloroaniline (31% of the added substrate in 90 min). Smaller amounts of 3-chloroaniline-N-glucuronide and 3-chloroacetanilide were formed (7 and 17% of the added 3-chloronitrobenzene, respectively, in 90 min). 4-Chloronitrobenzene was metabolized to 4-chloroacetanilide, 4-chloroaniline, and S-(4-nitrophenyl)glutathione in approximately equal amounts (10-15% of the added substrate in 90 min). Studies with hepatic microsomes showed that reduction of the chloronitrobenzenes to chloroanilines was inhibited by SKF 525-A, metyrapone, and carbon monoxide, suggesting that cytochrome P-450 played a role in the reaction. Thus, the major difference in the in vitro hepatic metabolism of the three isomers of chloronitrobenzene is the failure of 3-chloronitrobenzene to be converted to a glutathione conjugate.
DMD articles become freely available 12 months after publication, and remain freely available for 5 years.Non-open access articles that fall outside this five year window are available only to institutional subscribers and current ASPET members, or through the article purchase feature at the bottom of the page.
|