DIET AND GLUCOSE-INDUCED CHANGES IN RAT DUODENAL AND PANCREATIC SEROTONIN AND PLASMA-GLUCOSE LEVELS

Serotonin concentrations in the duodenum and pancreas of rats fed 9,22 (control), and 45% protein diets for 21 days were analyzed 15 minutes before (fasting levels) and 45 minutes after an oral glucose load. Fasting levels of serotonin were significantly higher in the duodenum of rats consuming the low and high protein diets. Plasma glucose levels were significantly higher in fasted rats receiving the low protein diet. Glucose load caused a significant decrease in duodenal concentration of serotonin and an increase in pancreatic serotonin among rats fed all three diets. The results suggest that duodenal serotonin levels change in response to diet composition whereas pancreatic serotonin is altered by glucose load.