The purpose of the present study was to delineate the effect of
interferon-alpha(2b) (IFN-alpha(2b)) administration on the liver
regenerative capacity after partial hepatectomy in rats. The
administration of IFN-alpha(2b) simultaneously with partial hepatectomy
did not affect hepatic proliferation in a statistically significant
manner. When IFN-alpha(2b) was administered either 2 or 12 hr
postoperatively, an inhibition of hepatocyte proliferation was observed
24 hr postoperatively, while at further time intervals up to 48 hr, DNA
synthesis remained similar to that observed in the simply partially
hepatectomized rats, The enzyme thymidine kinase (TK), has been
implicated in the suppression of proliferation in interferon-treated
cell cultures, In all IFN-alpha(2b)-treated groups of rats, alterations
of TK activity were observed without being correlated to the liver
regenerative status, Additionally, the administration of the polyamine
putrescine in partially hepatectomized rats treated at the time of
surgery with IFN strongly enhanced TK activity, but did not affect DNA
biosynthesis, In the above-mentioned in vivo model of controlled
cellular proliferation, the administration of IFN-alpha(2b) affected the
rate of hepatocyte proliferation depending on the time of its
administration; this effect was not correlated to the enzymatic activity
of TK, as inhibited TK activity is responsible for the suppressed DNA
synthesis in in vitro systems
