7 p. : il.Nucleotides and nucleosides represent an
important and ubiquitous class of molecules that interact
with specific receptors, regulate a variety of activities
within the liver, and play a role in the pathogenesis of
hepatic fibrosis. Ecto-nucleotide pyrophosphatase/phosphodiesterases
(E-NPPs) are ecto-enzymes that are located
on the cell surface. NPP1, NPP2, and NPP3 (abbreviated as
NPP1–3 hereafter) have been implicated in the hydrolysis
of nucleotides; together with other ecto-nucleotidases, they
control the events induced by extracellular nucleotides. We
have identified and compared the expression of E-NPP
family members in two different phenotypes of the mouse
hepatic stellate cell line (GRX). In quiescent-like hepatic
stellate cells (HSCs), E-NPP activity was significantly
higher, NPP2 mRNA expression decreased and NPP3
mRNA increased. The differential NPP activity and
expression in two phenotypes of GRX cells suggests that
they are involved in the regulation of extracellular nucleotide
metabolism in HSCs. However, the role of E-NPPs in
the liver remains to be clarifie
