ENTEROENDOCRINE CELLS IN THE DUODENUM PRODUCE A NUMBER OF HORMONES
SECRETIN WAS THE FIRST HORMONE TO BE DISCOVERED. IT CAUSES THE SECRETION OF A BICARBONATE
RICH SECRETION FROM THE PANCREAS, INCREASES INTESTINAL SECRETIONS, STIMULATES THE SECRETION OF BILE BY THE LIVER AND INHIBITS
GASTRIC SECRETIONS UNDER CERTAIN CONDITIONS.
CHOLECYSTOKININ (CCK) IS SECRETED BY ENTEROENDOCRINE CELLS IN THE DUODENAL WALL. IT STIMULATES
GALL BLADDER CONTRACTION, MOVING BILE INTO THE DUODENUM. IT ALSO STIMULATES THE SECRETION OF ENZYME RICH DIGESTIVE JUICE
FROM THE PANCREAS. IT CAUSES RELAXATION OF THE HEPATOPANCREATIC SPHINCTER AND ALSO CAN INHIBIT GASTRIC SECRETIONS
UNDER CERTAIN CONDITIONS.
GASTRIN IS ALSO PRODUCED BY THE DUODENUM. IT INCREASES GASTRIC
SECRETION AND EMPTYING BY INCREASING GASTRIC MOTILITY AND RELAXING THE PYLORIC SPHINCTER.
GASTRIC INHIBITORY PEPTIDE IS PRODUCED BY THE DUODENUM AND THE PROXIMAL PORTIONS OF THE
JEJUNUM. IT INHIBITS GASTIC SECRETIONS AND DECREASES GASTRIC MOTILITY.
GASTRIC INHIBITORY PEPTIDE IS SECRETED BY THE EPITHELIAL CELLS OF THE DUODENUM.
IT INHIBITS GASTRIC MOTILITY AND THE SECRETION OF HCL BY THE STOMACH.
GIP IS SOMETIMES CALLED GLUCOSE DEPENDENT INSULINOTROPIC PEPTIDE BECAUSE IT ENHANCES THE SECRETION OF INSULIN.
