+1 Recommend
0 collections
      • Record: found
      • Abstract: found
      • Article: not found

      In vitro glucuronidation of fenofibric acid by human UDP-glucuronosyltransferases and liver microsomes.

      Drug metabolism and disposition: the biological fate of chemicals

      Cell Line, Fenofibrate, analogs & derivatives, metabolism, Glucuronides, chemistry, Glucuronosyltransferase, Humans, Isoenzymes, Microsomes, Liver, enzymology, Recombinant Proteins

      Read this article at

          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.


          Fenofibric acid (FA), the active moiety of fenofibrate, is an agonist of the peroxisome proliferator-activated nuclear receptor alpha that modulates triglyceride and cholesterol profiles. Lipid response to fenofibrate and FA serum concentrations is highly variable. Although FA is reported to be almost exclusively inactivated by UDP-glucuronosyltransferases (UGTs) into FA-glucuronide (FA-G), the contribution of UGT isoenzymes has never been systematically assessed. Heterologously expressed human UGT1A and UGT2B and their coding variants were tested for FA glucuronidation using liquid chromatography/mass spectrometry. Recombinant UGT2B7 presented the highest V(max)/K(m) value (2.10 microl/min/mg), 16-fold higher than the activity of other reactive UGTs, namely, UGT1A3, UGT1A6, and UGT1A9 (0.13, 0.09, and 0.02 microl/min/mg, respectively). UGT2B7.1 (His(268)) and UGT2B7.2 (Tyr(268)) enzyme activity was similar, whereas UGT1A3.2 (R(11)A(47)), UGT1A3.3 (Trp(11)), and UGT1A9.3 (Thr(33)) showed 61 to 96% reduced V(max)/K(m) values compared with the respective (1) reference proteins. FA-G formation by a human liver bank (n = 48) varied by 10-fold, but the rate of formation was not associated with common genetic variations in UGT1A3, UGT1A6, UGT1A9, and UGT2B7. Correlation with activities for the probe substrates zidovudine (UGT2B7; r(2) = 0.75), mycophenolic acid (UGT1A9; r(2) = 0.42), fulvestrant (UGT1A3; r(2) = 0.36), but not serotonin (UGT1A6; r(2) = 0.06) indicated a primary role for UGT2B7 and lesser roles of UGT1A9 and UGT1A3 in hepatic FA glucuronidation. This was confirmed by a strong correlation of FA-G formation with UGT2B7 protein content and inhibition by fluconazole, a known UGT2B7 selective inhibitor. Additional studies are required to identify genetic factors contributing to the observed FA glucuronidation variability.

          Related collections

          Author and article information



          Comment on this article