Mode of exocrine pancreatic function and regulation in pigs at weaning

The development of the mechanisms regulating pancreatic functions are still largely unknown. In an attempt to address this issue the development of th e enteropancreatic reflexes regulating pancreatic secretion were followed b y measuring the blood plasma levels of some essential GI hormones in young pigs from 3 weeks of age and up to a few weeks after weaning. Exogenous secretin stimulated the exocrine pancreas before weaning, while o nly a slight increase in trypsin output occurred after exogenous CCK admini stration before weaning. The exocrine pancreas did not response to intraduo denal (id) stimulation with intact protein, amino acids or lipid, indicatin g that mechanisms regulating the exocrine pancreas that are based on entero pancreatic reflexes evoked by protein and fat either do not exist or are no t fully developed before and directly after weaning. Moreover, the lack of any stimulation of pancreatic secretion by duodenal acidification suggests that the HCl-dependent enteropancreatic reflex does not function in pigs at the age studied. However, the increasing stimulation of pancreatic protein output seen with id infusion of oleic acid in the oldest post weaning pigs studied indicates that the stimulation of enteropancreatic reflexes evoked by fatty acids in young pigs is brought on by weaning. The changes observed in the basal level of GI tract hormones in the blood p lasma, i.e., decreased basal plasma CCK, glucagon and somatostatin levels a nd increased secretin and insulin levels can be related to increased pancre atic secretion around weaning.