Characterization of xenobiotic metabolizing enzymes in bovine small intestinal mucosa
Article first published online: 8 OCT 2009
© 2009 Blackwell Publishing Ltd
Journal of Veterinary Pharmacology and Therapeutics
Volume 33, Issue 3, pages 295–303, June 2010
How to Cite
VIRKEL, G., CARLETTI, M., CANTIELLO, M., DELLA DONNA, L., GARDINI, G., GIROLAMI, F. and NEBBIA, C. (2010), Characterization of xenobiotic metabolizing enzymes in bovine small intestinal mucosa. Journal of Veterinary Pharmacology and Therapeutics, 33: 295–303. doi: 10.1111/j.1365-2885.2009.01137.x
- Issue published online: 7 MAY 2010
- Article first published online: 8 OCT 2009
- (Paper received 24 June 2009; accepted for publication 2 September 2009)
Virkel, G., Carletti, M., Cantiello, M., Della Donna, L., Gardini, G., Girolami, F., Nebbia, C. Characterization of xenobiotic metabolizing enzymes in bovine small intestinal mucosa. J. vet. Pharmacol. Therap.33, 295–303.
The intestinal mucosa plays a capital role in dictating the bioavailability of a large array of orally ingested drugs and toxicants. The activity and the expression of several xenobiotic metabolizing enzymes were measured in subcellular fractions from the duodenal mucosa of male veal calves and beef cattle displaying a functional rumen but differing in both age (about 8 months vs. 18 to 24 months) and dietary regimens (i.e., milk replacer plus hay and straw vs. corn and concentrated meal). Intestinal microsomes showed cytochrome P450 (CYP) 2B, 2C- and 3A-mediated activities and the presence of the corresponding immunorelated proteins, but no proof of CYP1A expression and/or functions could be provided. Intestinal microsomes were also active in performing reactions typically mediated by carboxylesterases (indophenylacetate hydrolysis), flavin-containing monooxygenases (methimazole S-oxidation), and uridindiphosphoglucuronyltransferases (1-naphthol glucuronidation), respectively. Cytosolic fractions displayed the glutathione S-transferase (GST)-dependent conjugation of 1-chloro-2,4-dinitrobenzene; besides, the GST-mediated conjugation of ethacrinic acid (GSTπ) or cumene hydroperoxide (GSTα) was matched by the presence of the corresponding immunorelated proteins. Conversely, despite the lack of measurable activity with 3,4-dichloronitrobenzene, a protein cross reacting with anti-rat GSTμ antibodies could be clearly detected. Although, as detected by densitometry, CYPs and GST isoenzymes tended to be more expressed in beef cattle than in veal calf preparations, there was a general poor correlation with the rate of the in vitro metabolism of the selected diagnostic probes.