Abstract
Induction of drug enzyme activity in the intestine can strongly determine plasma levels of drugs. It is therefore important to predict drug-drug interactions in human intestine in vitro. We evaluated the applicability of human intestinal precision-cut slices for induction studies in vitro. Morphological examination and intracellular ATP levels indicated tissue integrity up to 24 h of incubation, whereas in proximal jejunum slices, the metabolic rate toward most substrates remained at 40 to 50% of initial values. In colon slices, the cytochrome P450 conversions were below the detection limit, but conjugation rates remained relatively constant during incubation. The inducibility of drug-metabolizing enzymes and P-glycoprotein was evaluated using prototypical inducers for five induction pathways. β-Naphthoflavone (aryl hydrocarbon receptor ligand) induced CYP1A1 (132-fold in colon and 362-fold in proximal jejunum) and UDP glucuronosyltransferase (UGT) 1A6 mRNA (9.8-fold in colon and 3.2-fold in proximal jejunum). In proximal jejunum, rifampicin (RIF) [pregnane X receptor (PXR) ligand] induced CYP3A4 (5.2-fold), CYP2B6 (2-fold), UGT1A6 (2.2-fold), and multidrug resistance-1 (MDR1)/ABCB1 mRNA (2.7-fold), whereas 6β-hydroxytestosterone formation (CYP3A4) increased 2-fold. In colon, RIF induced UGT1A6 32-fold and MDR1 2.2-fold. Dexamethasone (glucocorticoid receptor and PXR ligand) induced CYP3A4 mRNA (3.5-fold) and activity (5-fold) in proximal jejunum. Phenobarbital (constitutive androstane receptor activator) induced CYP3A4 (4.1-fold, only in jejunum), CYP2B6 (4.9-fold in colon and 2.3-fold in proximal jejunum), and MDR1/ABCB1 mRNA and CYP3A4 activity (2-fold only proximal jejunum). Quercetin (nuclear factor-E2-related factor 2 activator) induced UGT1A6 mRNA (6.7-fold in colon and 2.2-fold in proximal jejunum). In conclusion, this study shows that human intestinal precision-cut slices are useful to study induction of drug-metabolizing enzymes and transporters in the human intestine.
Footnotes
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This study was supported by the Technology Foundation STW, the applied science division of NWO and the technology programme of the Ministry of Economic Affairs, and Yamanouchi Europe.
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Article, publication date, and citation information can be found at http://dmd.aspetjournals.org.
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doi:10.1124/dmd.107.018820.
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ABBREVIATIONS: DME, drug-metabolizing enzyme; DTs, drug transporters; PXR, pregnane X receptor; TT, testosterone; 17β-HSD, 17β-hydroxysteroid dehydrogenase activity; 7EC, 7-ethoxycoumarin; 7HC, 7-hydroxycoumarin; UGT, UDP glucuronosyltransferase; BNF, β-naphthoflavone; AhR, aryl hydrocarbon receptor; RIF, rifampicin; DEX, dexamethasone; GR, glucocorticoid receptor; PB, phenobarbital; CAR, constitutive androstane receptor; Q, quercetin; Nrf2, nuclear factor-E2-related factor 2; MDR1, multidrug resistance-1; DMSO, dimethyl sulfoxide; 7HC-GLUC, 7-hydroxycoumarin glucuronide; TOH, hydroxytestosterone; ACN, acetonitrile; MeOH, methanol; PCR, polymerase chain reaction; HPLC, high-performance liquid chromatography; P450, cytochrome P450.
- Received September 11, 2007.
- Accepted December 18, 2007.
- The American Society for Pharmacology and Experimental Therapeutics
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