The protein products of the immediate early genes (IEG)s have been proposed to play an important role in long-term tissue plasticity such as cell repair or programmed cell death. The expression of liver IEGs was studied following liver ischemia (LI) or OLT in rats. In LI, 60 min of warm ischemia was induced in shunted rats (shunt LI group; 100% survival) and nonshunted rats (nonshunted LI group; poor survival). In OLT, donor livers were transplanted into the recipients within 1 hr (fresh liver OLT group; 100% survival) or after 24 hr of storage using University of Wisconsin solution (preserved liver OLT group; poor survival). Using both models, IEG mRNAs (c-fos and c-jun) were analyzed by Northern blot hybridization at various times before and after reperfusion. The expression of liver IEGs was not induced by warm ischemia and cold preservation alone. Reperfusion of livers following warm ischemia or cold preservation resulted in a distinctly different pattern of gene expression in viable and nonviable livers. In shunted LI and fresh liver OLT groups (viable), c-fos and c-jun mRNAs increased markedly to a peak value within 1-2 hr of reperfusion, returning to basal level by 3 hr. In nonviable livers, the level of these mRNAs was detected continuously at 3 hr of reperfusion in the nonshunted LI model and also at 6 hr after reperfusion in the preserved liver OLT group. Our data suggest that a protracted pattern of expression of c-fos and c-jun in the liver at the early stage of reperfusion might be correlated with the severity of liver transplant-related insults and subsequent graft failure.