摘要：To clarify the metabolic fate of fenitrothion at low concentration, the detoxication of fenitrooxon (FO) which will serve as an integral part of the metabolic conversion of fenitrothion was investigated. FO at concentration around 10-6M reacted with mouse liver homogenate and disappeared immediately. This occurred mostly in the soluble fraction of mouse liver, and was dependent on glutathione (GSH), and the only metabolite detected was desmethyl-FO. On the other hand, since hydrolysis by arylesterase (AEase) did not occur, 4-nitro-m-cresol was not detected. These facts reveal that, at such low concentration, FO is detoxified solely through desmethylation reaction catalyzed by GSH S-transferase (GTase). The Km and Vmax values of both GTase and AEase for FO are also consistent with this reaction mechanism, i.e. detoxication of FO at higher concentration may be attributable to both GTase and AEase, but at low concentration only GTase will be responsible.
