VPB 121: Veterinary Physiology - II (2+1)

HORMONAL REGULATION

• Secretin and CCK are the important hormones regulate  pancreatic secretion.
• Secretin is the gastro intestinal hormone secreted by the duodenal  mucosa of small intestine. Presence of acid ingesta, peptides, soaps and amino acids, HCl in the stimulate the release of secretin. When the duodenal pH falls below 4.0 secretin causes increased  secretion of  thin watery pancreatic juice with high concentration of HCO₃ with less or no enzyme referred  as hydrolytic secretion. This type of HCO₃ release is to neutralise the acidity of duodenal contents.  It inhibits gastric secretion.
• Cholecystokinin (CCK)  stimulates the pancreatic secretion rich in enzymes referred as  ecbolic secretion identical to the action of vagal stimulation.   CCK also causes contraction of gall bladder and also delays gastric emptying.
• Vasoactive intestinal polypeptide (VIP) another intestinal hormone, stimulates pancreatic HCO₃ secretion, whereas the pancreatic polypeptide, inhibits pancreatic HCO₃ and enzyme secretions.