AFLATOXIN CARCINOGENESIS - INHIBITION OF LIVER CANCER INDUCTION IN HYPOPHYSECTOMIZED RATS

Intact and hypophysectomized male rats were fed aflatoxin at a dose (4 μg/g in diet) sufficient to produce liver cancers in all of the 14 intact rats surviving 49 weeks. Fourteen hypophysectomized rats also survived this latent period, but no liver tumors were induced although the animals received aflatoxin at a higher rate than the intact control animals. However, tumors of extrahepatic tissues—particularly of the retro‐orbital lacrimal glands—were induced in the hypophysectomized rats. The selective blockade of hepatocarcinogenesis by hypophysectomy previously known with aminoazo dyes and fluorenamines is therefore extended to a new class of chemicals, the aflatoxins. It is suggested that aflatoxins may require metabolic activation before becoming effective carcinogens for rat liver. Copyright © 1969 Wiley‐Liss, Inc., A Wiley Company