Secretagogue-induced enzyme release from the exocrine pancreas of rats following adaptation to a high protein diet.

The mechanisms of pancreatic adaptation to dietary changes and whether these changes are reflected in the serum are not fully understood. The present study investigates secretagogue-induced release of digestive enzymes from dispersed pancreatic acini as well as the concentrations of these enzymes in serum and pancreas after adaptation to a high protein diet. Adult rats were fed an 8.5% casein diet ad libitum. After 14 d the rats were divided into three groups and fed isoenergetic diets constituting 8.5, 24 or 40% protein for an additional 6 d. No significant differences in final body weight or pancreatic weight were observed among the groups of rats. Rats adapted to the 40% protein diet showed significantly higher trypsin and chymotrypsin activity in pancreatic homogenates than rats fed the 8.5% protein diet. These changes in pancreatic enzyme content were not reflected in serum. Pancreatic acini isolated from the 8.5% protein group showed a markedly reduced responsiveness to cholecystokinin (CCK-8), secretin- and carbachol-induced enzyme release in comparison to the other two dietary groups, although basal enzyme release was the same in all groups. These results indicate that the secretion of pancreatic enzymes following a physiological stimulus is affected by a low protein, high carbohydrate diet.