TY - JOUR T1 - Induction of Human UDP Glucuronosyltransferases (UGT1A6, UGT1A9, and UGT2B7) by <em>t</em>-Butylhydroquinone and 2,3,7,8-Tetrachlorodibenzo-<em>p</em>-Dioxin in Caco-2 Cells JF - Drug Metabolism and Disposition JO - Drug Metab Dispos SP - 569 LP - 573 VL - 27 IS - 5 AU - Peter A. Münzel AU - Stefan Schmohl AU - Horst Heel AU - Katharina Kälberer AU - Barbara S. Bock-Hennig AU - Karl Walter Bock Y1 - 1999/05/01 UR - http://dmd.aspetjournals.org/content/27/5/569.abstract N2 - Human colon carcinoma Caco-2 cells were used to study the induction of UDP glucuronosyltransferase (UGT) isoforms UGT1A6, UGT1A9, and UGT2B7 by aryl hydrocarbon receptor agonists and by antioxidant-type inducers with 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) andt-butylhydroquinone (TBHQ), respectively. Early- (PF11) and late-passage clones (TC7) of Caco-2 cells, which show low and high constitutive UGT1A6 expression, respectively, were selected. The following results were obtained: 1) In Caco-2 cells UGT activity (4-methylumbelliferone as substrate) was significantly enhanced by 10 nM TCDD or 40 to 80 μM TBHQ and 2) duplex reverse-transcription-polymerase chain reaction analysis showed for the first time that the expression of human UGT1A6, UGT1A9, and UGT2B7 was enhanced by 40 to 80 μM TBHQ; both UGT1A6 and UGT1A9 were induced by 10 nM TCDD, whereas UGT2B7 was not induced by TCDD. The results suggest that at least two human UGTs (UGT1A6 and UGT1A9) are inducible by aryl hydrocarbon receptor agonists and even more isoforms (UGT1A6, UGT1A9, and UGT2B7) are inducible by antioxidant-type inducers in Caco-2 cells. The American Society for Pharmacology and Experimental Therapeutics ER -