title: Degradation to sulphate of S-methyl-L-cysteine sulphoxide and S-carboxymethyl-L-cysteine sulphoxide in man.
abstract: A nearly complete recovery of radioactivity was achieved over 14 days following the oral administration of [35S]-S-methyl-L-cysteine sulphoxide and [35S]-S-carboxymethyl-L-cysteine sulphoxide to four healthy male volunteers. The urine was the major pathway of excretion of radioactivity (c. 96% in 0-14 days; c. 59% in 0-24 hours), with the faecal route being relatively unimportant (c. 1.7% in 0-3 days). Inorganic sulphate was an important degradation product, incorporating a substantial proportion of radioactive sulphur derived from these molecules (c. 40% in 0-14 days; c. 20% in 0-24 hours). Subtle differences were noted in the pattern of radioactive sulphate excretion following administration of the two cysteine-sulphoxide compounds, suggesting that their sulphur-containing moieties may enter different catabolic routes.
authors.affiliation: School of Biosciences, University of Birmingham, Birmingham, UK.
authors.forename: R H
authors.initials: RH
authors.lastname: Waring
authors.forename: R M
authors.initials: RM
authors.lastname: Harris
authors.forename: G B
authors.initials: GB
authors.lastname: Steventon
authors.forename: S C
authors.initials: SC
authors.lastname: Mitchell
mesh_terms: D000284:Administration, Oral; D000328:Adult; D001673:Biodegradation, Environmental; D002233:Carbocysteine / Q000493:pharmacokinetics* / Q000652:urine; D003545:Cysteine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics* / Q000652:urine; D005243:Feces / Q000737:chemistry; D006801:Humans; D008297:Male; D013431:Sulfates / Q000378:metabolism / Q000652:urine*; D013462:Sulfur Radioisotopes
chemical_list: D013431:Sulfates; D013462:Sulfur Radioisotopes; C008389:methiin; D002233:Carbocysteine; D003545:Cysteine