Increase of a form of UDP-glucuronyltransferase glucuronizing various phenolic xenobiotics and the corresponding translatable mRNA in 3-methylcholanthrene-treated rat liver.
Induction of hepatic microsomal UDP-glucuronyltransferase activity toward various phenolic xenobiotics by 3-methylcholanthrene treatment of rats was observed, and the process of the induction was studied. We had previously purified a form of UDP-glucuronyltransferase (called GT-1) having a catalytic activity toward phenolic xenobiotics from liver microsomes of 3-methylcholanthrene-treated rats. The antibodies against GT-1 inhibited the enzyme activity toward those xenobiotics in liver microsomes, and bound to a single protein having a molecular weight of about 54,000 Da (same value as that of GT-1) among microsomal proteins on immunoblotting analysis. The amount of GT-1 protein in hepatic microsomes was found to be increased in close correspondence with the activity increase by 3-methylcholanthrene treatment, by immunoblotting analysis using an uninducible cytochrome P-450 reductase as a negative standard. It was shown by in vitro translation assays that the protein increase described above resulted from the enhancement of the level of translatable mRNA encoding for GT-1. Increases in the amount of the protein immunochemically corresponding to GT-1 in the microsomes from liver of phenobarbital-treated rats and from extrahepatic organs, such as kidney, small intestine, and lung, of phenobarbital- or 3-methylcholanthrene-treated rats were also observed.
Yokota
H
H
Department of Veterinary Biochemistry, School of Veterinary Medicine, Rakuno Gakuen University, Hokkaido.
Yuasa
A
A
D000818:Animals; D004591:Electrophoresis, Polyacrylamide Gel; D004790:Enzyme Induction / Q000187:drug effects; D014453:Glucuronosyltransferase / Q000096:biosynthesis*; D015151:Immunoblotting; D008297:Male; D008748:Methylcholanthrene / Q000494:pharmacology*; D008862:Microsomes, Liver / Q000187:drug effects / Q000201:enzymology*; D009928:Organ Specificity; D010636:Phenols / Q000378:metabolism*; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000096:biosynthesis / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains
D010636:Phenols; D012333:RNA, Messenger; D008748:Methylcholanthrene; D014453:Glucuronosyltransferase