High accumulation of 2,3,4,7,8-pentachlorodibenzofuran to hepatic microsomes of rats.

The tissue and subcellular distributions of 14C-2,3,4,7,8-pentachlorodibenzofuran (PenCDF), one of the most important causal agents of yusho, were studied using rats. More than 60% of the radioactivity given orally was accumulated in the liver after 5 d and this high percentage persisted over a period of 3 weeks. Subcellular fractionation of the liver homogenate showed unusual separation by PenCDF-pretreatment, but the distribution of radioactivity was just parallel to those of cytochrome P-450 content and glucose-6-phosphatase (EC3.1.3.9) activity. Gas chromatographic analysis provided evidence that the extracts from the liver and its subcellular fractionations contained only unchanged PenCDF. Those results strongly suggest that PenCDF has some affinity to endoplasmic reticulum of rat liver.