Major involvement of rabbit liver cytochrome P4501A in thiabendazole 5-hydroxylation

Article abstract of DOI:10.3109/00498259609046747

1. Thiabendazole is a widely used food preservative and anthelmintic drug for breeding animal species. In order to characterize precisely the cytochrome P450 isozyme(s) involved in its major route of metabolism, a rapid and sensitive spectrofluorimetric method was developed for the simultaneous determination of thiabendazole and its main hepatic metabolite 5-hydroxythiabendazole. 2. The kinetics of thiabendazole 5-hydroxylation were determined in microsomal preparations from control rabbits or animals previously treated with either β-naphthoflavone, isosafrole, phenobarbital, rifampicin or clofibrate. These treatments led to specific induction of CYP1A1, 1A2, 2B4, 3A6 and 4A1 respectively. 3. By considering this panel of characterised microsomal preparations, only those obtained from BNF-treated rabbits exhibited an increase in thiabendazole 5-hydroxylase activity. Ethoxyresorufin O-deethylation in these microsomes was solely inhibited by thiabendazole. These argue for a specific involvement of the CYP1A, subfamily. 4. In the CYP1A subfamily, CYP1A2 appears to be responsible for basal 5-hydroxylation and further unidentified metabolism of thiabendazole in control livers. However, the major involvement of CYP1A1 is supported by the following characteristics of 5-hydroxylation of thiabendazole: (1) the correlation with CYP1A1 expression and (2) the inhibition by ellipticine and not by furafylline, inhibitors of CYP1A1 and CYP1A2 respectively. 5. All these data demonstrated that the rabbit cytochrome P4501A is predominantly involved in thiabendazole 5-hydroxylation which has been suspected to be critical in terms of safety of the parent drug.

Full text of DOI:10.3109/00498259609046747

Xenobiotica
the fate of foreign compounds in biological systems
ISSN: 0049-8254 (Print) 1366-5928 (Online) Journal homepage: http://www.tandfonline.com/loi/ixen20
Major involvement of rabbit liver cytochrome
P4501A in thiabendazole 5-hydroxylation
X. Rey-grobellet, C. Eeckhoutte, J. F. Sutra, M. Alvinerie & P. Galtier
To cite this article: X. Rey-grobellet, C. Eeckhoutte, J. F. Sutra, M. Alvinerie & P. Galtier (1996)
Major involvement of rabbit liver cytochrome P4501A in thiabendazole 5-hydroxylation,
Xenobiotica, 26:7, 765-778, DOI: 10.3109/00498259609046747
To link to this article: http://dx.doi.org/10.3109/00498259609046747
Published online: 22 Sep 2008.
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Date: 23 March 2016, At: 15:32