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Journal of Integrative Agriculture  2014, Vol. 13 Issue (1): 158-166    DOI: 10.1016/S2095-3119(13)60335-4
Animal Science · Veterinary Science Advanced Online Publication | Current Issue | Archive | Adv Search |
Metabolism of Mequindox in Isolated Rat Liver Cells
 LIGuang-hui12, SHANQi1, WANGJing1, LIYa-fei1, GAOYan1, ZENGZhen-ling1
1.National Reference Laboratory of Veterinary Drug Residues (SCAU), College of Veterinary Medicine, South China Agricultural University,
Guangzhou 510642, P.R.China
2.Jie Yang Entry-Exit Inspection and Quarantine Bureau, Jieyang 522031, P.R.China
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摘要  Mequindox (MEQ), 3-methyl-2-quinoxalinacetyl-1,4-dioxide, is widely used in Chinese veterinary medicine as an antimicrobial agent and feed additive. Its toxicity has been reported to be closely related to its metabolism. To understand the pathways underlying MEQ’s metabolism more clearly, we studied its metabolism in isolated rat liver cells by using liquid chromatography coupled with electrospray ionization hybrid linear trap quadrupole orbitrap (LC-LTQ-Orbitrap) mass spectrometry. The structures of MEQ metabolites and their product ions were readily and reliably characterized on the basis of accurate MS2 spectra and known structure of MEQ. Eleven metabolites were detected in isolated rat liver cells, two of which were detected for the first time in vitro. The major metabolic pathways reported previously for in vitro metabolism of MEQ in rat microsomes were confirmed in this study, including N → O group reduction, carbonyl reduction, and methyl monohydroxylation. In addition, we found that acetyl hydroxylation was an important pathway of MEQ metabolism. The results also demonstrate that cellular systems more closely simulate in vivo conditions than do other in vitro systems such as microsomes. Taken together, these data contribute to our understanding of the in vivo metabolism of MEQ.

Abstract  Mequindox (MEQ), 3-methyl-2-quinoxalinacetyl-1,4-dioxide, is widely used in Chinese veterinary medicine as an antimicrobial agent and feed additive. Its toxicity has been reported to be closely related to its metabolism. To understand the pathways underlying MEQ’s metabolism more clearly, we studied its metabolism in isolated rat liver cells by using liquid chromatography coupled with electrospray ionization hybrid linear trap quadrupole orbitrap (LC-LTQ-Orbitrap) mass spectrometry. The structures of MEQ metabolites and their product ions were readily and reliably characterized on the basis of accurate MS2 spectra and known structure of MEQ. Eleven metabolites were detected in isolated rat liver cells, two of which were detected for the first time in vitro. The major metabolic pathways reported previously for in vitro metabolism of MEQ in rat microsomes were confirmed in this study, including N → O group reduction, carbonyl reduction, and methyl monohydroxylation. In addition, we found that acetyl hydroxylation was an important pathway of MEQ metabolism. The results also demonstrate that cellular systems more closely simulate in vivo conditions than do other in vitro systems such as microsomes. Taken together, these data contribute to our understanding of the in vivo metabolism of MEQ.
Keywords:  mequindox       isolated rat liver cells       metabolism       metabolites       LC-LTQ-Orbitrap  
Received: 10 August 2012   Accepted:
Fund: 

The work was financially supported by the National Basic Research Program of China (2009CB118800)

Corresponding Authors:  ZENG Zhen-ling, Tel: +86-20-85281204, Fax: +86-20-85284896, E-mail: zlzeng@scau.edu.cn   
About author:  ZENG Zhen-ling, Tel: +86-20-85281204, Fax: +86-20-85284896, E-mail: zlzeng@scau.edu.cn

Cite this article: 

LIGuang-hui12 , SHANQi1 , WANGJing1 , LIYa-fei1 , GAOYan1 , ZENGZhen-ling1 . 2014. Metabolism of Mequindox in Isolated Rat Liver Cells. Journal of Integrative Agriculture, 13(1): 158-166.

A i t i o A. 1978. Conjugation reactions in drug biotransformation. In: Proceedings of the Symposium on Conjugation Reactions in Drug Biotransformation. Held in Turku, Finland. July 23-26, 1978 Elsevier/North- Holland Biomedical Press, The Netherlands.

Bi Y, Wang X, Xu S, Sun L, Zhang L, Zhong F, Wang S, Ding S, Xiao X. 2011. Metabolism of olaquindox in rat and identification of metabolites in urine and feces using ultra-performance liquid chromatography/quadrupole time-of-flight mass spectrometry. Rapid Communications in Mass Spectrometry, 25, 889-898

 Chen Z L. 2006. Veterinary Pharmacology. China Agricultural Press, Beijing. pp. 239-241 (in Chinese)

Dougherty K K, Spilman S D, Green C E, Steward A R, Byard J L. 1980. Primary cultures of adult mouse and rat hepatocytes for studying the metabolism of foreign chemicals. Biochemical Pharmacology, 29, 2117-2124

 Fry J R, Bridges J W. 1977. A novel mixed hepatocyte- fibroblast culture system and its use as a test for metabolism-mediated cytotoxicity. Biochemical Pharmacology, 26, 969-973

 Ganley B, Chowdhury G, Bhansali J, Daniels J S, Gates K S. 2001. Redox-activated, hypoxia-selective DNA cleavage by quinoxaline 1,4-di-N-oxide. Bioorganic & Medicinal Chemistry, 9, 2395-2401

 Green C E, Dabbs J E, Tyson C A. 1983. Functional integrity of isolated rat hepatocytes prepared by whole liver vs. biopsy perfusion. Analytical Biochemistry, 129, 269-276

 Green C E, Segall J H, Byard J L. 1981. Metabolism, cytotoxicity, and genotoxicity of the pyrrolizidine alkaloid senecionine in primary cultures of rat hepatocytes. Toxicology and Applied Pharmacology, 60, 176-185

 Herebian D, Lamshoft M, Mayatepek E, Spiekerkoetter U. 2010. Identification of NTBC metabolites in urine from patients with hereditary tyrosinemia type 1 using two different mass spectrometric platforms: triple stage quadrupole and LTQ-Orbitrap. Rapid Communications in Mass Spectrometry, 24, 791-800

 Högberg J, Kristoferson A. 1977. A correlation between glutathione levels and cellular damage in isolated hepatocytes. European Journal of Biochemistry, 74, 77-82

 Huang X J, Ihsan A, Wang X, Dai M H, Wang Y L, Su S J, Xue X J, Yuan Z H. 2009. Long-term dose-dependent response of Mequindox on aldosterone, corticosterone and five steroidogenic enzyme mRNAs in the adrenal of male rats. Toxicology Letters, 191, 167-173

 Huang X J, Wang X, Ihsan A, Liu Q, Xue X J, Su S J, Yang C H, Zhou W, Yuan Z H. 2010. Interactions of NADPH oxidase, renin-angiotensin-aldosterone system and reactive oxygen species in mequindox-mediated aldosterone secretion in Wistar rats. Toxicology Letters, 198, 112-118

 Ihsan A, Wang X, Liu Z, Wang Y, Huang X, Liu Y, Yu H, Zhang H, Li T, Yang C, et al. 2011. Long-term mequindox treatment induced endocrine and reproductive toxicity via oxidative stress in male Wistar rats. Toxicology and Applied Pharmacology, 252, 281-288

 Jeejeebhoy K N, Bruce-Robertson A, Ho J, Kida S, Muller- Eberhard U. 1976. Synthesis of hemopexin with and without hormonal supplementation in rat hepatocyte suspensions: comparison with that of albumin and of fibrinogen. Canadian Journal of Biochemistry, 54, 74-78

 Kalgutkar A S, Hatch H L, Kosea F, Nguyen H T, Choo E F, McClure K F, Taylor T J, Henne K R, Kuperman A V, Dombroski M A, et al. 2006. Preclinical pharmacokinetics and metabolism of 6-4-(2,5-difluorophenyl)oxazol-5-yl)-3-isopropyl- [1,2,4]-triazolo[4,3-a]pyridine, a novel and selective p38alpha inhibitor: identification of an active metabolite in preclinical species and human liver microsomes

 Biopharmaceutics & Drug Disposition, 27, 371-386

 Lim H K, Chen J, Sensenhauser C, Cook K, Subrahmanyam V. 2007. Metabolite identification by data-dependent accurate mass spectrometric analysis at resolving power of 60,000 in external calibration mode using an LTQ/ Orbitrap. Rapid Communications in Mass Spectrometry, 21, 1821-1832

 Liu Z Y, Huang L L, Chen D M, Yuan Z H. 2010. Metabolism of mequindox in liver microsomes of rats, chicken and pigs. Rapid Commun Mass Spectrom, 24, 909-918

 Shan Q, Liu Y, He L, Ding H, Huang X, Yang F, Li Y, Zeng Z. 2012. Metabolism of mequindox and its metabolites identification in chickens using LC-LTQ-Orbitrap mass spectrometry. Journal of Chromatography (B), 881-882, 96-106

 Stacey N H, Klaassen C D. 1981. Inhibition of lipid peroxidation without prevention of cellular injury in isolated rat hepatocytes. Toxicology and Applied Pharmacology, 58, 8-18

 Vadi H, Moldeus P, Capdevila J, Orrenius S. 1975. The metabolism of benzo(alpha)pyrene in isolated rat liver cells. Cancer Research, 35, 2083-2091

 Zhong X, Zhang Y, An Y. 2008. Influence of different drugs and route of administration on curative effect of piglets white scour. Livestock and Poultry Industry, 11, 3.
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