Phase 2 Metabolites of N-Hydroxylated Amidines (Amidoximes): Synthesis, in Vitro Formation by Pig Hepatocytes, and Mutagenicity Testing

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• 作者：Bernd Clement ; Kai Christiansen ; and Ulrich Girreser
• 刊名：Chemical Research in Toxicology
• 出版年：2001
• 出版时间：March 2001
• 年：2001
• 卷：14
• 期：3
• 页码：319 - 326
• 全文大小：149K
• 年卷期：v.14,no.3(March 2001)
• ISSN：1520-5010

文摘

A pig hepatocyte culture system was used for phase 2 biotransformation studies in vitro.The viability of the cultured hepatocytes was characterized daily during cultivation by lactatedehydrogenase release into the supernatant and albumin synthesis of the cells. The metabolicactivity of the hepatocyte cultures was measured by 7-ethoxycoumarin (ECOD) and 7-ethoxyresorufin O-deethylation (EROD). The viability and metabolic activity of these pig hepatocyteswere preserved for several days by culturing the cells in a monolayer culture system. Besidesthe known reduction of N-hydroxylated benzamidine (benzamidoxime) (2) to benzamidine (1),glucuronidation and, to a much smaller extent, sulfation of 2 to benzamidoxime O-glucuronide(3) and benzamidoxime O-sulfate (4) by cultured pig hepatocytes were found. The analyseswere performed using HPLC and LC/MS studies. For unequivocal assignment, the hithertounknown metabolites 3 and 4 were synthesized and characterized by spectroscopic techniques.Examination of benzamidoxime O-glucuronide and benzamidoxime O-sulfate for mutagenicityby means of the Ames test revealed that both phase 2 conjugates have no mutagenic effects inthe TA98 and TA100 strains. So the phase 2 conjugation of benzamidoxime is significant interms of detoxification.