Effect of endotoxin and cortisone on synthesis of ribonucleic acid and protein in livers of mice.

The effect of cortisone and endotoxin, singly and in combination, on ribonucleic acid (RNA) synthesis in livers of adrenalectomized mice was determined. This was accomplished by measuring the incorporation either of inorganic (32)P or of (14)C-orotic acid into the RNA. Under similar conditions, the effect of these agents on the rate of protein synthesis was examined with the use of (14)C-leucine. Bacterial endotoxin was found to augment the uptake of isotope in the RNA and in the protein of the liver. These reactions did not appear to be mediated via the pancreatic hormone insulin, which was found to depress the incorporation of the radioactive compounds into RNA. Cortisone increased the uptake of isotope in liver RNA but depressed the incorporation of leucine into hepatic protein. These results indicate that the previously observed ability of endotoxin to prevent the hormone induction of hepatic enzymes, such as tryptophan oxygenase, is not associated with impaired synthesis of liver RNA or protein.