Promoting effect of o-aminoazotoluene on hepatocarcinogenesis is accompanied by the increase in inflammatory and proliferative processes in liver tissue and decrease in the concentration of free thyroxin in the blood.

o-Aminoazotoluene in noncarcinogenic doses promoted the development of liver tumors in female ICR mice induced by administration of diethylnitrosamine during early ontogeny. Severe inflammatory infiltration and proliferation of oval cells were found in liver tissue of these animals. The concentration of free thyroxin decreased in the blood. Our results supplement published data that promoters of hepatocarcinogenesis inhibit thyroid function.