TY - JOUR T1 - Glucuronidation of Retinoids by Rat Recombinant UDP: Glucuronosyltransferase 1.1 (Bilirubin UGT) JF - Drug Metabolism and Disposition JO - Drug Metab Dispos SP - 889 LP - 893 VL - 25 IS - 7 AU - Anna Radominska AU - Joanna M. Little AU - Paul A. Lehman AU - Victor Samokyszyn AU - Gladys R. Rios AU - Christopher D. King AU - Mitchell D. Green AU - Thomas R. Tephly Y1 - 1997/07/01 UR - http://dmd.aspetjournals.org/content/25/7/889.abstract N2 - Rat liver recombinant BR1UGT1.1 was found to have significant activity toward retinoid substrates. UGT1.1 glucuronidation activity was 91 ± 18 pmol/mg × min for atRA and 113 ± 19 pmol/mg × min for 5,6-epoxy-atRA. The apparentKM and Vmax of atRA acid glucuronidation by UGT1.1 were 59.1 ± 5.4 μM and 158 ± 43 pmol/mg × min, respectively. SDS-PAGE and Western blot analysis of UGT1.1-transfected HK293 membrane proteins photolabeled with [11,12-3H]atRA revealed a protein of ∼56 kDa that was labeled by [3H]atRA, detected by anti-pNP UGT antibody and not present in membranes from nontransfected HK293 cells. Liver microsomes from Gunn rats, which lack UGT1.1, had significant activity toward atRA (111 ± 28 pmol/mg × min). The American Society for Pharmacology and Experimental Therapeutics ER -