Decrease of interferon-induced 2',5'-oligoadenylate synthetase activity in cirrhotic rat liver.

We evaluated the effect of hepatic fibrosis on the induction of hepatic 2',5'-oligoadenylate synthetase (2-5AS) by interferon (IFN) in a rat model of liver cirrhosis, induced with thioacetamide. Although there was no difference in serum 2-5AS activity between the control and cirrhotic rats given murine IFN, 2-5AS activity in the liver homogenates of cirrhotic rats was significantly lower than in the controls (105 +/- 18.5 vs. 171 +/- 10.2 pmol/micrograms, p < 0.01). These results suggested that hepatic fibrosis attenuated the effect of IFN and one of the reasons for this may be the decreased induction of hepatic 2-5AS activity after IFN administration in the presence of a cirrhotic liver.