Histopathology of the rat liver following a single autoprotective dose of 3′‐methyl‐4‐dimethylaminoazobenzene

Abstract

Male inbred Leeds strain rats were given single intragastric doses of 1200 mg/kg of 3'-methyl-4-dimethylaminoazobenzene, autoprotective against liver necrosis and then sacrificed at intervals up to 14 months. About 40 per cent of the animals died, apparently as a result of pancreatic necrosis, between 9 and 13 days after treatment while the remainder survived until they were killed. The liver changes induced included an early intense ductular cell reaction, presistent hepatocellular abnormalities and at later stages, cholangiofibrosis and increasing numbers of parenchymal clear cells. Although no tumours arose as a result of treatment, the observed histopathological changes are similar to those seen during liver carcinogenesis induced by a variety of carcinogens and may be due specifically to the carcinogenic action of the azo dye.

Serum alpha‐fetoprotein in rats after ligation of the common bile duct: Relation to ductular cell (oval cell) proliferation

“…Our morphological and histochemical investigations confirm that the two lines of ductular cells and hepatocytes remain distinct at all stages of the proliferation of epithelium that follows ligation of the common bile duct in this species and offer no support for the possibility of transformations. Flaks and Flaks (1978) discussed the possibility of two types of ductular cell proliferations with and without carcinogenic potential. Ianoka (1967) and Iwasaki et al (1972) suggested that the oval cells appearing in azo-dye carcinogenesis may be precursors of hepatocytes.…”