Effect of Hypophysectomy or p-Hydroxypropiopfaenone on Hepatic Preeancerous Changes in Rats Given Thioacetamide or 3′Methyl-4-Dimethylaminoazobenzene

Summary

When either thioacetamide or 3′ methyl-4-dimethylaminoazobenzene (3′Me-DAB) was injected intraabdominally into rats, liver adenylic acid (5′AMP) deaminase activity was significantly increased. When these two carcinogens were administered to hypophysectomized rats, the 5′AMP deaminase activity of thioacetamide injected rats was increased, but not that of 3′Me-DAB injected animals. Incorporation patterns of orotic acid-6¹⁴C into two sub-fractions of rat liver nuclear RNA among thioacetamide injected rats were not affected by hypophy-sectomy. Feeding p-hydroxypropiophenone (PHP) to rats failed to diminish the increase in liver 5′AMP deaminase activity caused by thioacetamide, whether fed or injected. But, increases caused by injections of 3′Me-DAB were inhibited. The relationship between the endocrine status of the rat and the conversion of thioacetamide and 3′Me-DAB to proximate carcinogens was discussed.