Biochemical studies of toxic agents. 10. Observations on the metabolism of 35S-labelled mercapturic acids

Abstract

1-Naphythyl(s35)mercapturic acid and p-bromophenyl (S35)mercapturic acid were isolated from the urine of rats dosed with naphthalene and bromobenzene respectively and given L-(S35)-cystine immediately afterwards by another route. Phenyl(S35)mercapturic acid was prepared by the debromination of p-bromophenyl-(S35)mercapturic acid. Observations were made on the influence of administration of naphthalene on the excretion of S35 by rats dosed with L-(S35) cystine. The distribution of S35 in the feces and the sulfur fractions of the urine was studied after the administration of l-naphthyl(s35)-mercapturic acid to rats. Little of the S35 was excreted in the feces. Most of it appeared in the neutral sulfur fraction of the urine, and about 1/3 was accounted for in the urine as l-naphthylmer-capturic acid. Less than 4% of the administered S35 was present in the urine as inorganic sulfate, and less than 1% as ethereal sulfate. The excretion of S35 by rats dosed with phenyl-(S35) mercapturic acid or p-bromophenyl (S35) mercapturic acid resembled that observed when 1-naphthyl(s35) mercapturic acid was administered.