Effect of thioacetamide on cytochrome P-450 synthesis in rat liver

A single injection of thioacetamide to rats results in a striking decrease in liver cytochrome P-450. The drug blocks the phenobarbitone-mediated induction of cytochrome P-450b. Under these conditions, there is a decrease in the synthesis of cytochrome P-450b, which is essentially due to a decrease in the amount of translatable mRNA for cytochrome P-450b. This effect of thioacetamide is not due to a general effect on protein synthesis or polyribosome stability. Multiple injections of thioacetamide also decrease the synthesis of cytochrome P-450b and the amounts of its translatable mRNA.