Glucuronidation of 4-methylumbelliferone and 4-hydroxybiphenyl and in vitro induction of UDP-glucuronosyltransferase 2B12-mRNA in precision-cut rat liver slices.
Fresh rat liver slices were used to demonstrate the glucuronidation of the model substrates 4-methylumbelliferone (MU) and 4-hydroxybiphenyl (HB). Both glucuronidation reactions proved to be more stable than cytochrome P450-dependent monooxygenations. After an incubation time of 48 h there was no decrease in MU glucuronidation rate, whereas HB glucuronidation was stable until 24 h, and then decreased by about 50% until 48 h. The technique of quantitative competitive RT-PCR was used to determine the expression of UDP-glucuronosyltransferase 2B12-mRNA (UGT2B12-mRNA) in precision-cut rat liver slices. Constitutive levels of UGT2B12-mRNA were measurable. Following 24 h culture of rat liver slices in the presence of phenobarbital, the level of UGT2B12-mRNA increased about twofold, which corresponds to the inducibility in vivo. The addition of beta-naphthoflavone had no influence. The results show that precision-cut liver slices are not only suitable for the detection of an in vitro induction of cytochrome P450-mRNAs, which is characterized by high induction factors, but also of poor induction effects, e.g. on UGT2B12-mRNA, provided that the respective mRNA is exactly quantified.
Pissowotzki
Klaus
K
Institute of Pharmacology and Toxicology, Friedrich-Schiller-University Jena, Germany.
Glöckner
Reinhild
R
Müller
Dieter
D
D000818:Animals; D021461:Animals, Outbred Strains; D001713:Biphenyl Compounds / Q000494:pharmacology*; D004790:Enzyme Induction; D015971:Gene Expression Regulation, Enzymologic; D020719:Glucuronides / Q000378:metabolism; D014453:Glucuronosyltransferase / Q000096:biosynthesis* / Q000235:genetics; D006923:Hymecromone / Q000494:pharmacology*; D008099:Liver / Q000187:drug effects / Q000201:enzymology*; D008297:Male; D008867:Microtomy; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D020133:Reverse Transcriptase Polymerase Chain Reaction
D001713:Biphenyl Compounds; D020719:Glucuronides; D012333:RNA, Messenger; D006923:Hymecromone; C019046:4-phenylphenol; D014453:Glucuronosyltransferase