2,3,7,8-Tetrachlorodibenzo-p-dioxin affects retinol esterification in rat hepatic stellate cells and kidney

2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), a highly toxic environmental contaminant, interferes with retinoid homeostasis. To elucidate the underlying mechanism, the activities of lecithin : retinol and acyl-CoA : retinol acyltransferase (LRAT and ARAT) were determined in liver, kidney, and hepatic parenchymal and nonparenchymal cell fractions from rats 7 days after a single oral dose of 10 μg TCDD/kg body weight (b.w). Severely depressed LRAT activity in hepatic stellate cells, and greatly increased LRAT activity in kidneys, as well as decreased ARAT activity in stellate cells, were seen in TCDD-treated rats. Although the relevance of decreased ARAT activity under physiological conditions is not clear, the changed LRAT activities most likely contributes significantly to the TCDD-induced effects on tissue retinyl ester levels. It is intriguing that TCDD affects LRAT activity in hepatic stellate cells and kidney in opposite directions. The results suggest that effects of TCDD on retinyl ester tissue levels could be due to a specific interaction with retinoid metabolism.