PROTEIN SYNTHESIS AND RIBONUCLEIC ACID METABOLISM IN MOUSE PANCREAS IN VITRO AFTER WHOLE BODY IRRADIATION WITH x-RAYS

Several workers have been unable to find any correlation between ribonucleic acid (RNA) synthesis and the incorporation of isotopically labeled amino acids into tissue protein after treatment of animals with x-rays.In particular, Abrams (1) found that in bone marrow and intestine x-rays inhibited the synthesis in vivo of RNA and DNA (deoxyribonucleic acid) as measured by the rates of incorporation of glycine-l-Cl4 into these substances and lowered the RNA concentration, but they had little effect on the incorporation of glycine-l-Cl4 into total precipitable protein.The working hypothesis at the beginning of the present investigation was that RNA may not be concerned with peptide bond synthesis per se as measured by amino acid incorporation into proteins, but that it may play a role in the formation of specific proteins of biological activity.Thus an alteration in the structure of RNA or an interruption of its synthesis following large doses of x-rays might inhibit the synthesis of specific proteins but have little effect on amino acid incorporation into the total protein.The system used was the synthesis in vitro of a specific protein, the digestive enzyme amylase, by mouse pancreas (2).It was soon found that x-rays had no appreciable effects on RNA metabolism in the pancreas nor was enzyme synthesis inhibited under the conditions used.In fact the most interesting observation made was that under some conditions the rate of amylase synthesis was found to be increased 2-to S-fold 24 hours after irradiation.EXPERIMENTAL