PROPACHLOR DETOXICATION IN THE SMALL-INTESTINE - CYSTEINE CONJUGATION

14C-labeled 2-(S-cysteinyl)-N-isopropylacetanilide was recovered from media of everted rat small intestine sacs incubated in media that contained [14C]propachlor (2-chloro-N-isopropyl-[1-14C]acetanilide). The metabolite was identified by chromatographic characteristics and mass spectra of the butyl ester-trifluoroacetamide derivative. The cysteinyl conjugate formed during small intestine incubations. Although the glutathione conjugate was not 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 [a herbicide] in the media showed that capacity to metabolize propachlor to polar metabolites was approximately the same throughout the small intestine length.