Expression of a high-affinity form of UDP-glucuronosyltransferase in human foetal liver cells in culture on exposure to mercuric chloride.
The activity of UDP-glucuronosyltransferase (UDPGT, EC 2.4.1.17) in human foetal liver cells in culture was measured with two acceptor substrates, namely harmol and 1-naphthol. There was a dose-dependent increase of about 10-400% in UDPGT activity when the cells were exposed to 1-30 microM-HgCl2. Above a critical concentration of 30 microM-HgCl2, the heavy metal ion was toxic to the cells. Kinetic studies of the glucuronidation reaction with harmol and 1-naphthol showed that Hg2+ ions seemed to induce the expression of a high-affinity form of UDPGT, which was absent from the normal controls. The dramatic increase in specific activity in UDPGT was accompanied by a parallel increase in Vmax. measured with harmol and UDP-glucuronic acid. The significance of a possible induction of UDPGT in human foetal liver cells by HgCl2 is discussed.
Tan
T M
TM
Department of Biochemistry, Faculty of Medicine, National University of Singapore.
Wong
K P
KP
Sit
K H
KH
D002478:Cells, Cultured; D003513:Cycloheximide / Q000494:pharmacology; D014453:Glucuronosyltransferase / Q000378:metabolism*; D006247:Harmine / Q000031:analogs & derivatives / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D008099:Liver / Q000187:drug effects / Q000196:embryology* / Q000201:enzymology; D008627:Mercuric Chloride / Q000494:pharmacology*; D009284:Naphthols / Q000378:metabolism
D009284:Naphthols; C029350:1-naphthol; C001326:harmol; D006247:Harmine; D008627:Mercuric Chloride; D003513:Cycloheximide; D014453:Glucuronosyltransferase