The effect of aflatoxin B1 on the hepatic structure and RNA synthesis in rats fed a diet marginally deficient in choline.

Aflatoxin, a potent hepatotoxin, causes rapid inhibition of RNA polymerase activity in isolated rat liver nuclei. Its hepatotoxicity is accompanied by an injury of periportal parenchymal cells. Rats fed a diet marginally deficient in choline are protected against the acutely toxic action of aflatoxin B! . This diet does not prevent the rapid inhibition of RNA polymerase or the changes in nucleolar morphol ogy following the administration of aflatoxin B,. The diet does however largely prevent the proliferation of smooth endoplasmic reticulum and the necrosis of periportal paren chymal cells. The diet appears to offer the possibility of separating those changes in the liver associated with hepato toxicity from those associated with hepatocarcinogenicity.