Effects of T-2 toxin were studied in primary cultures of adult rat hepatocytes. Hepatocytes were isolated by a collagenase perfusion technique and cultured as monolayer in serum-free media for 48 hours. Uptake of cardiac glycoside (ouabain), hormonal induction of $\alpha$-aminoisobutyric acid (AIB) uptake and tyrosine aminotransferase (TAT) activity were used as the parameters to determine cytotoxicity. No significant lethality was observed after 6 hours treatment of 100 ng T-2 toxin/ml. At does from 10 to 100 ng/ml, T-2 toxin inhibited the induction of AIB transport and TAT activity when T-2 toxin was added simultaneously with hormones. It also exerted inhibitory effects when added at 6 hours prior to the hormonal treatment, and removed from medium. Meanwhile, T-2 toxin did not show any inhibitory effects on ouabain transport system. The results of this study suggest that T-2 toxin caused abnormality to liver functions within the testing period, but it does not due to membrane damage and lethal effect. It seems likely that T-2 toxin is a strong inhibitor of protein synthesis in rat hepatocytes.