Carcinogenesis, Vol 19, 1251-1255, Copyright © 1998 by Oxford University Press
BC Gallagher, DB Rudolph, BT Hinton and MH Hanigan
In carcinogen-treated rats, gamma-glutamyl transpeptidase (GGT) is induced
in preneoplastic liver lesions and liver tumors. However, in mice, GGT is
rarely detected during hepatocarcinogenesis. Data in this study reveal that
GGT is not induced in mouse hepatocytes when they are maintained in vitro
under the same conditions that induce GGT activity in primary cultures of
rat hepatocytes. GGT activity in rat hepatocytes increased 20-fold during
the first 7 days in culture, but there was no induction of GGT in primary
cultures of mouse hepatocytes. Comparison of intracellular glutathione
levels in rat and mouse liver cells showed that the glutathione level was
higher in the mouse liver cells than the rat. Blocking glutathione
synthesis with buthionine sulfoximine reduced the intracellular glutathione
concentration in mouse liver cells but did not trigger an induction of GGT.
Analysis of the GGT mRNA in primary cultures of rat hepatocytes showed that
only GGT mRNA(III) is induced. This is the same GGT mRNA species present in
preneoplastic hepatic lesions and liver tumors in the rat (1-3). Therefore
activation of promoter III in the GGT gene is responsible for induction of
GGT in both hepatocytes in vitro and liver tumors in vivo. These data show
that primary cultures of rat and mouse hepatocytes provide a model system
with which to study interspecies differences in the regulation of this
enzyme and to better understand the role of GGT in normal and neoplastic
processes.
ARTICLES
Differential induction of gamma-glutamyl transpeptidase in primary cultures of rat and mouse hepatocytes parallels induction during hepatocarcinogenesis
Department of Cell Biology, University of Virginia, Charlottesville 22908, USA.
![]()
CiteULike
Connotea
Del.icio.us What's this?
This article has been cited by other articles:
![]() |
G. Boanca, A. Sand, and J. J. Barycki Uncoupling the Enzymatic and Autoprocessing Activities of Helicobacter pylori {gamma}-Glutamyltranspeptidase J. Biol. Chem., July 14, 2006; 281(28): 19029 - 19037. [Abstract] [Full Text] [PDF] |
||||
