Effect of breed and gender on bovine liver cytochrome P450 3A (CYP3A) expression and inter-species comparison with other domestic ruminants

Abstract

-The cytochrome P450 (P450) superfamily represents a group of relevant enzymes in the field of drug metabolism and several exogenous or constitutional factors contribute to regulate its expression. Cattle represent an important source of animal-derived food-products and studies concerning the P450 expression are needed for the extrapolation of pharmacotoxicological data from one species to another and for the evaluation of the consumer's risk associated with the consumption of harmful residues found in foodstuffs. In the present study, possible breed-, genderand species-differences in P4503A (the P450 subfamily more expressed in the human liver) expression were studied in vitro in Piedmontese (PDM) and Limousin (LIM) meat cattle breeds of both sexes and in domestic Ruminants (cattle, sheep and goats). Cytochrome P450 and P4503A contents as well as CYP3A-dependent drug metabolising enzymes (DME) were measured in liver microsomes. Significant lower levels of P450 (P < 0.001) and P4503A (P < 0.05) contents were observed in PDM vs. LIM of both sexes; the P4503A-dependent DME activities were significantly (P values ranging from 0.05 up to 0.001) higher in PDM cattle, particularly in males. A gendereffect in DME activities was noticed (P < 0.05) only in PDM male cattle. With regards to the species, the expression of both P4503A apoprotein and some of the related DME activities were more pronounced in sheep (P < 0.01 vs. cattle) and in goats (P < 0.05 vs. sheep; P < 0.01 vs. cattle) than in cattle. The significant differences in P4503A expression observed in LIM and PDM cattle are consistent with previously published data on strain-and breed-differences pointed out in rats and men. As far as a possible sex-effect is concerned, no clear-cut evidence is likely to be drawn. Finally, P4503A expression was more relevant in small ruminants. ruminants / liver drug metabolism / CYP3A / gender / breed

Effect of Breed upon Cytochromes P450 and Phase II Enzyme Expression in Cattle Liver

“…Concerning CYP3A, both 6␤OH-T and 2␤OH-T activities pointed out significant differences among breeds, whereas ERDEM, ETDEM, and TAODEM ones did not. These contrasting results partially disagreed with those reported by Dacasto et al (2005), where significant differences, between PM and LIM cattle, were found for ERDEM, ETDEM, and 2␤OH-T. Out of ERDEM, whose protocol and the resulting catalytic activity in PM (the only used in both studies) were similar, methodological differences might be probably offered as a justification for such a discrepancy; for ETDEM, in terms of substrate concentration or instrument sensitivity; about 2␤OH-T, of more sensitivity and precision of the used method (HPLC). In this respect, the correlation analysis among catalytic activities and CYP3A4-like mRNA gave better coefficients with HPLC results, which indirectly suggest TST as a more specific and useful substrate to study CYP3A expression in cattle.…”

“…In this respect, the correlation analysis among catalytic activities and CYP3A4-like mRNA gave better coefficients with HPLC results, which indirectly suggest TST as a more specific and useful substrate to study CYP3A expression in cattle. The immunoblotting, where the same anti-rat CYP3A1/2 cited by Nebbia et al (2003) was used, gave contradictory results compared with catalytic activities (according to Dacasto et al, 2005) but consistent with CYP3A4-like mRNA.…”

“…Likewise, commercially available antibodies, raised toward human and rat antigens, were used for CYP1A, 2B, 2C, 2E, and 3A immunoblotting; in fact, to the best of the authors' knowledge, mono-or polyclonal antibodies directed to cattle antigens have not yet produced so far. In effect, such an approach has been already adopted, at least partly, in prior studies where cattle liver drug metabolism was compared with that of other ruminants, other farm animals, or reference species (i.e., the rat) as well (Sivapathasundaram et al, 2001(Sivapathasundaram et al, , 2003aMachala et al, 2003;Nebbia et al, 2003Nebbia et al, , 2004Szotáková et al, 2004;Dacasto et al, 2005;Gusson et al, 2006;Ioannides, 2006). On the contrary, bovinespecific primer pairs were designed for P450s and phase II enzyme isoform mRNA to be used in the relative quantification by means of quantitative real-time polymerase chain reaction (Q RT-PCR).…”

Illegal Drug Treatments and Drug Metabolism: Biomarkers or Not?

“…CYP3A-dependent DME activity and cross-reacting proteins have been demonstrated in cattle (Dacasto et al, 2005), whereas a new isoform (CYP3A 37 ) has been sequenced and cloned in poultry (Ourlin et al, 2000). Members of the CYP3A subfamily metabolize a great number of drugs, as well as relevant endogenous compounds (e.g.…”

“…CYP3A expression is induced by DEX, rifampicin, pregnenolone-16α-carbonitrile and phenobarbital (Cascales Angosto and Gómez-Lechón, 2004). Testosterone, erythromycin and ethylmorphine are generally recognised as CYP3A substrates, even in cattle (Dacasto et al, 2005;Machala et al, 2003;Sivapathasundaram et al, 2001;Szotáková et al, 2004). In vivo, the urinary 6β-hydroxycortisol/cortisol ratio has been identified as a suitable test for evaluating CYP3A activity (Galteau and Samsa, 2003).…”