A histochemical study of the liver lesion induced by 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin) in rats.

A histochemical study of plasma-membrane associated enzymes in rat liver demonstrated a significant lesion 3 days after a single oral dose of 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin). The complete loss of canalicular ATPase reaction in the parenchymal cells of the centrilobular zone remained the prominent feature of the liver throughout the 6-wk period studied. Involvement of the periportal and midzonal regions occurred in moribund animals and improvement in the health of two surviving animals at 9 mth was associated with a normal distribution of ATPase in the liver. Qualitative changes in 5-nucleotidase and acid phosphatase were secondary to the parenchymal cell damage. This lesion supports the morphological evidence, reported previously, that the parenchymal cell plasma-membrane is a specific subcellular site of the toxic action of dioxin.