P>Objective The effect of corticosterone on both antizyme mRNA and protein levels in early regenerating rat liver induced by partial hepatectomy (PH) was investigated. Methods Bilateral adrenalectomies (ADX) were performed 3 days before PH. Corticosterone in sesame oil was injected subcutaneously to ADX rats. Antizyme mRNA and its protein level were examined by RT-PCR and Western blotting respectively. Results When compared with control (n=6, the same below) group, there were no significant changes in antizyme mRNA levels in ADX, 10 and 20 mg/kg body weight corticosterone-treated groups, whereas 40 mg/kg body weight corticosterone treatment markedly induced antizyme mRNA expression. Antizyme protein content in ADX group decreased significantly at 5, 7 and 9 hours after PH, however, it could be stimulated in a dosedependent manner following corticosterone administration during the whole experiment observed, particularly, at 5 hours post-PH antizyme protein levels in 10, 20 and 40 mg/kg body weight corticosterone-treated rats increased by 43%, 79% and 93% respectively, as compared with control group at the same time point. Conclusion Corticosterone may dose-dependently induce antizyme protein synthesis in early regenerating rat liver; 10 or 20 mg/kg body weight corticosterone treatment has little effect on antizyme mRNA level, but 40 mg/kg body weight corticosterone stimulates antizyme gene transcription./P>