Propachlor detoxication in the small intestine: Cysteine conjugation

Abstract

¹⁴ C‐Labeled 2‐(S‐cysteinyl)‐N‐isopropylacetanilide was recovered from the media of everted sacs of rat small intestine incubated in media that contained [ ¹⁴ C]propachlor (2‐chloro‐N‐isopropyl‐[1‐ ¹⁴ C]acetanilide). The metabolite was identified on the basis of chromatographic characteristics and mass spectra of the butyl ester‐trifluoro‐acetamide derivative. This evidence shows that the cysteinyl conjugate was formed during incubations of the small intestine. Although the glutathione conjugate has not been isolated from the intestine, it is a likely precursor of the cysteinyl metabolite. Data from experiments conducted with 10 ^‐5 and 10 ^‐4 M propachlor in the media showed that the capacity to metabolize propachlor to polar metabolites was approximately the same throughout the length of the small intestine.