The metabolism of benzyl isothiocyanate and its cysteine conjugate in guinea-pigs and rabbits.
1. Following oral administration of benzyl isothiocyanate or its cysteine conjugate the major metabolite isolated from urine of guinea-pigs and rabbits was a cyclic mercaptopyruvate conjugate, 4-hydroxy-4-carboxy-3-benzylthiazolidin-2-thione. 2. Renal excretion of the metabolite after oral administration of benzyl isothiocyanate or its cysteine conjugate to guinea-pigs amounted to 23% and 33% respectively. The corresponding N-acetylcysteine conjugate of benzyl isothiocyanate (a mercapturic acid) was present as a minor metabolite. 3. After oral or i.v. administration of the glutathione, cysteinylglycine, cysteine or N-acetylcysteine conjugates of benzyl isothiocyanate to guinea-pigs, the major metabolite in urine was 4-hydroxy-4-carboxy-3-benzylthiazolidin-2-thione, with the N-acetylcysteine conjugate of benzyl isothiocyanate present in traces only. 4. It is concluded that during formation of the cyclic mercaptopyruvate conjugate, the cysteine conjugate predominantly undergoes transamination, and only a small proportion undergoes N-acetylation.
D000818:Animals; D055598:Chemical Phenomena; D002621:Chemistry; D002855:Chromatography, Thin Layer; D003545:Cysteine / Q000031:analogs & derivatives* / Q000378:metabolism; D006168:Guinea Pigs; D017879:Isothiocyanates; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D011817:Rabbits; D013844:Thiazoles / Q000652:urine; D053778:Thiazolidines; D013861:Thiocyanates / Q000378:metabolism*
D017879:Isothiocyanates; D013844:Thiazoles; D053778:Thiazolidines; D013861:Thiocyanates; C036482:S-(N-benzylthiocarbamoyl)cysteine; C036481:4-hydroxy-4-carboxy-3-benzylthiazolidin-2-thione; C031403:benzyl isothiocyanate; D003545:Cysteine