ABSTRACT
The effect of different food substrates on production by the duodenal mucosa of factors acting on the endocrine and exocrine functions of the pancreas was studied in the rat in vivo. Intragastric loads of glucose, maltose, arginine, lysine, peanut oil or a protein hydrolysate (Nesmida) were given to a first group of rats. The duodenum was removed at various times after food and extracts of duodenal mucosa were injected into the pancreatic-duodenal artery of other rats. The effect of these extracts was determined by measuring immunoreactive insulin levels in the portal vein and amylase, trypsin and lipase activities in the pancreatic juice of this second series of rats. Glucose and arginine, but not lysine, increased the activity of duodenal extracts on insulin secretion, whereas oil ingestion modified the activity of the duodenal extracts by inhibiting insulin secretion. Duodenal mucosa extracts taken 30 min after glucose and maltose ingestion stimulated amylase but not trypsin in the pancreatic juice, whereas extracts taken 45 min after ingestion of a protein hydrolysate stimulated trypsin but not amylase production. The extracts taken after oil ingestion specifically stimulated lipase secretion. These observations suggest the possibility of a hormonal system which is modulated by various food substrates and influences both endocrine and exocrine pancreas functions.
