Effect of prototypical inducers on ligand activated nuclear receptor regulated drug disposition genes in rodent hepatic and intestinal cells.
OBJECTIVE
The aim of this study was to investigate the impact on expression of mRNA and protein by paradigm inducers/activators of nuclear receptors and their target genes in rat hepatic and intestinal cells. Furthermore, assess marked inter laboratory conflicting reports regarding species and tissue differences in expression to gain further insight and rationalise previously observed species differences between rodent and human based systems.


METHODS
Quantitative real time-polymerase chain reaction (QRT-PCR) and immunoblots were used to assess messenger RNA (mRNA) and protein expression for CYP2B2, CYP3A1, CYP3A2, CYP3A9, ABCB1a, ABCB1b, ABCC1, ABCC2, pregnane X receptor (PXR), farnesoid X receptor (FXR) and constituitive androstane receptor (CAR) in rat hepatoma cell line H411E, intestinal cells, Iec-6, and rat primary hepatocytes, in response to exposure for 18 h with prototypical inducers.


RESULTS
Dexamethasone (DEX) and pregnenolone 16alpha carbonitrile (PCN) significantly induced PXR, CYP3A9, ABCB1a and ABCB1b. However, when co-incubated, DEX appeared to restrict PCN-dependent induction. Chenodeoxycholic acid (CDCA) was the only ligand to induce FXR in all three cell types. Despite previously reported species differences between PCN and rifampicin (RIF), both compounds exhibited a similar profile of induction.


CONCLUSIONS
Data presented herein may explain some of the discrepancies previously reported with respect to species differences from different laboratories and have important implications for study design.
Martin
Philip
P
Department of Pharmacology and Therapeutics, The University of Liverpool, Pembroke Place, Liverpool, UK. P.Martin@liverpool.ac.uk
Riley
Robert
R
Thompson
Paul
P
Williams
Dominic
D
Back
David
D
Owen
Andrew
A
D000818:Animals; D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000378:metabolism; D002460:Cell Line; D045744:Cell Line, Tumor; D004790:Enzyme Induction / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects*; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000166:cytology / Q000187:drug effects; D008024:Ligands; D008113:Liver Neoplasms / Q000378:metabolism; D000089762:Multidrug Resistance-Associated Protein 2; D016133:Polymerase Chain Reaction; D011485:Protein Binding; D012333:RNA, Messenger / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D018160:Receptors, Cytoplasmic and Nuclear / Q000187:drug effects* / Q000378:metabolism; D013045:Species Specificity
C000715087:ABCC2 protein, human; D008024:Ligands; D000089762:Multidrug Resistance-Associated Protein 2; D012333:RNA, Messenger; D018160:Receptors, Cytoplasmic and Nuclear