Coordinate induction by antioxidants of UDP-glucuronosyltransferase UGT1A6 and the apical conjugate export pump MRP2 (multidrug resistance protein 2) in Caco-2 cells

Treatment of Caco-2 cells with the antioxidants quercetin or t-butylhydroquinone Led to induced protein levels of UDP-glucuronosyltransferase UGT1A6 (ca. 3-fold. over controls) and of the apical conjugate export pump multidrug resistance protein 2 (MRP2; 1.9-fold. ol-er controls). In contrast to UGT1A6, MRP2 (symbol ABCC2) was not inducible by 2,3,7,8-tetrachlorodibenzo-p-dioxin. Immunocytochemistry demonstrated. that MRP2 was only expressed at the brush border domain of Caco-2 cell monolayers. The results indicate that UGT1A6 and MRP2 are coordinately induced by antioxidants, facilitating chemoprotection against phenolic toxins and excretion of conjugates into the intestinal lumen. (C) 2000 Elsevier Science Inc.