Constitutive expression and activity of cytochrome P450 in conventional pigs.

Pigs have often been suggested to be a useful model for humans, when investigating CYP dependent events, like drug metabolism. However, comprehensive knowledge about the constitutive expression of the major CYP and corresponding transcription factors is limited. We compared the constitutive mRNA expression of aryl hydrocarbon receptor, constitutive androstane receptor and pregnane X receptor and CYP1A1, CYP1A2, CYP2A, CYP2E1 and CYP3A in liver, adipose tissue, muscle and small intestine in pigs, as well as the expression along the length of the small intestine and colon. Tissue samples were taken from female pigs, and analyzed for gene expression, as well as CYP dependent activity using qPCR and specific probe substrates, respectively. For all investigated transcription factors and CYPs the mRNA expression and activity was highest in the liver. CYP1A1 and CYP3A mRNA expression and activity was shown in all investigated tissues. Along the small intestine and colon the mRNA expression and activity of CYP1A1 and CYP3A was gradually decreased. The results demonstrated, similarity to that reported for humans, and hence adds to the use of pigs as a model for humans.