Effect of breed upon cytochromes P450 and phase II enzyme expression in cattle liver.
Cattle represent an important source of animal-derived food-products; nonetheless, our knowledge about the expression of drug-metabolizing enzymes (DMEs) in present and other food-producing animals still remains superficial, despite the obvious toxicological consequences. Breed represents an internal factor that modulates DME expression and catalytic activity. In the present work, the effect of breed upon relevant phase I and phase II DMEs was investigated at the pretranscriptional and post-translational levels in male Charolais (CH), Piedmontese (PM) and Blonde d'Aquitaine (BA) cattle. Because specific substrates for cattle have not yet been identified, the breed effect upon specific cytochrome P450 (P450), UDP-glucuronosyltransferase (UGT), or glutathione S-transferase (GST) DMEs, in terms of catalytic activity, was determined by using human marker substrates. Among P450s, benzphetamine N-demethylase, 16beta-, 6beta-, and 2beta-testosterone hydroxylase, aniline and p-nitrophenol hydroxylase, and alpha-naphthol and p-nitrophenol UGT activities were significantly higher in CH; in contrast, lower levels of CYP1A1-, CYP1A2-, CYP2B6-, CYP2C9-, CYP2C18-, CYP3A4-, and UGT1A1-like mRNAs were noticed, with CH < PM < or = BA as a trend. CYP2B and CYP3A mRNA results were confirmed with immunoblotting, too. As regards conjugative DMEs, UGT1A6-like mRNA levels were consistent with respective catalytic activities. Both 1-chloro-2,4-dinitrobenzene and 3,4-dichloronitrobenzene GST activities were higher in BA, and these results agreed with GSTA1-, GSTM1-, and GSTP1-like mRNA amounts. Correlation analysis between catalytic activities and mRNAs showed either significant or uneven results, depending on the substrate. These findings confirm previous data obtained in laboratory species; however, further studies are required to ascribe this behavior to pretranscriptional or post-translational phenomena.
Giantin
Mery
M
Dipartimento di Sanità Pubblica, Patologia Comparata ed Igiene Veterinaria, Area di Farmacologia e Tossicologia, Viale dell'Università 16, I-35020 Agripolis Legnaro (Padova), Italy.
Carletti
Monica
M
Capolongo
Francesca
F
Pegolo
Sara
S
Lopparelli
Rosa Maria
RM
Gusson
Federica
F
Nebbia
Carlo
C
Cantiello
Michela
M
Martin
Pascal
P
Pineau
Thierry
T
Dacasto
Mauro
M
D000818:Animals; D002417:Cattle / Q000235:genetics*; D003577:Cytochrome P-450 Enzyme System / Q000235:genetics* / Q000378:metabolism; D020869:Gene Expression Profiling; D014453:Glucuronosyltransferase / Q000235:genetics* / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D005982:Glutathione Transferase / Q000235:genetics* / Q000378:metabolism; D008099:Liver / Q000378:metabolism; D008297:Male; D008862:Microsomes, Liver / Q000378:metabolism; D009251:NADPH-Ferrihemoprotein Reductase / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D013045:Species Specificity
D012333:RNA, Messenger; D003577:Cytochrome P-450 Enzyme System; D009251:NADPH-Ferrihemoprotein Reductase; D014453:Glucuronosyltransferase; D005982:Glutathione Transferase; D005978:Glutathione