TCDD inhibits the normal accumulation of vitamin A in the hepatic stellate cells, which constitute the main storage site for vitamin A. In this study we investigated if the reduced capacity of stellate cells to store vitamin A could be due to cell transformation or cytotoxicity. Livers from rats exposed to TCDD were immunohistochemically stained for markers of normal and transformed stellate cells. The results show that the TCDD-induced inhibition of hepatic vitamin A accumulation is neither due to a reduction in the number of stellate cells nor to transformation of the cells.