Acute fine structural changes in rat hepatocytes induced by a single large dose of 2-acetylaminofluorene.

Male rats were given a single intragastric dose of 2-acetylaminofluorene, 600 mg/kg body weight, killed at intervals up to 14 days after treatment, and their hepatic tissue examined by electron microscopy. The early cytoplasmic lesion produced in hepatocytes by lower doses, consisting of perinuclear glycogen pooling, peripheral displacement of organelles and pyknosis, was delayed for several days. Among the changes which appeared to be independent of this lesion were disorganization and decrease of the granular endoplasmic reticulum and abnormalities of the bile canaliculi. These changes were similar to those which are seen during chronic exposure to 2-AAF and other hepatocarcinogens and in hepatic cell tumours.