Effect of feeding diets of different composition on the protein synthetic pattern of the rat pancreas.

Rats were fed a protein-rich or carbohydrate-rich diet for 3 weeks. By means of a double-label technique, we compared the protein-synthesizing patterns under these conditions. After 3 weeks of feeding, the relative rates of all the identified secretory enzymes and of some unidentified components had changed. The synthetic rates of the proteolytic proenzymes and of ribonuclease were increased after feeding a protein-rich diet, whereas those of the amylases and of lipase were lowered. The protein synthetic patterns of the rat pancreas under two extreme feeding conditions were compared to that of the pancreas of rats constantly fed a balanced diet of an intermediate composition. The results indicated that changes in relative rate of synthesis are mainly provoked by the protein-rich diet. Only the synthetic rate of the anodic chymotrypsinogen was strongly influenced by the carbohydrate-rich diet.