Contribution of the different UDP-glucuronosyltransferase (UGT) isoforms to buprenorphine and norbuprenorphine metabolism and relationship with the main UGT polymorphisms in a bank of human liver microsomes.

Contribution of the different UDP - glucuronosyltransferase ( UGT ) isoforms to buprenorphine and norbuprenorphine metabolism

Human UDP-glucuronosyltransferase, UGT1A8, glucuronidates dihydrotestosterone to a monoglucuronide and further to a structurally novel diglucuronide.

We identified human UDP-glucuronosyltransferase (UGT) isoforms responsible for producing dihydrotestosterone (DHT) diglucuronide, a novel glucuronide in which the second glucuronosyl moiety is attached at the C2' position of the first glucuronosyl moiety, leading to diglucuronosyl conjugation of a single hydroxyl group of DHT at the C17 position. Incubation of the DHT monoglucuronide with 12 cD...

Determination of drug glucuronidation and UDP-glucuronosyltransferase selectivity using a 96-well radiometric assay.

A rapid and sensitive radiometric assay for UDP-glucuronosyltransferase (UGT) is described. UGT substrates are incubated in 96-well plates with microsomes in the presence of [14C]UDP-glucuronic acid, and 14C-labeled glucuronidation products are separated from the unreacted nucleotide sugar by solid-phase extraction using 96-well extraction plates. The assay was validated with 15 structurally di...

Prediction of drug clearance by glucuronidation from in vitro data: use of combined cytochrome P450 and UDP-glucuronosyltransferase cofactors in alamethicin-activated human liver microsomes.

Glucuronidation via UDP-glucuronosyltransferase (UGT) is an increasingly important clearance pathway. In this study intrinsic clearance (CL(int)) values for buprenorphine, carvedilol, codeine, diclofenac, gemfibrozil, ketoprofen, midazolam, naloxone, raloxifene, and zidovudine were determined in pooled human liver microsomes using the substrate depletion approach. The in vitro clearance data in...

Coimmunoprecipitation of UDP-glucuronosyltransferase isoforms and cytochrome P450 3A4.

Coimmunoprecipitation was used to investigate protein-protein interactions between several UDP-glucuronosyltransferase (UGT) isoforms and cytochrome P450 3A4. Solubilized human liver microsomes were incubated with specific antibodies to UGT2B7, UGT1A6, UGT1A1, and CYP3A4, and the immunoprecipitates were run on SDS-polyacrylamide gel electrophoresis. Western blots showed that UGT2B7, UGT1A6, UGT...