Effects of long-term dietary modifications on pancreatic enzyme activity

The effect of long-term dietary modification on pancreatic exocrine function in rats has been investigated by examining responses to cholecystokinin-pancreozymin stimulation, using a method of direct pancreatic duct cannulation. Residual pancreatic enzyme activity remaining in the whole pancreas following stimulation was also measured. After 6 months of dietary modification, changes in the pancreatic secretions of high-protein- or high-fat-fed animals were similar to those reported in short-term studies in which elevation of trypsin and lipase activity occurred in the pancreas. However, between 6 and 9 months, both volume and amylase activity of pancreatic secretions decreased in animals fed a high-protein diet. At 6 and 9 months, animals fed a high-carbohydrate diet had increased amounts of amylase and decreased trypsin in both pancreatic secretion and homogenate, similar to short-term changes previously reported. High-carbohydrate-fed animals had decreased lipase activity in pancreatic secretions, but lipase activity in pancreatic homogenates was increased, similar to levels found in animals fed a high-fat diet.