45-HORMONES OF GATROINTESTINAL TRACT – Dr. Venk Flashcards
Name 4 digestion related endocrine hormones.
Cholecystokinin (CCK), gastrin, gastric inhibitory peptide (GIP) and secretin.
Name the 4 cell types that secrete the respective GIT hormones.
Duodenal ‘K’ cells secrete GIP
duodenal ‘I’ cells secrete CCK
S cells secrete secretin
antral (G) cells secrete gastrin
Name the 2 families of GIT peptide hormones.
Secretin family of peptides: includes secretin, glucagons, VIP and GIP.
Gastrin family of peptides: includes gastrin and CCK. Identical C-terminal sequences of 1st 5 a.a.
Name the functions of gastrin.
Main functions of gastrin are to stimulate the release of HCl from the parietal cells of stomach and to regulate growth of the gastric mucosa. Stimulated by food and inhibited by secretin and somatostatin.
What is the secretion signal for CCK?
CCK released in response to certain a.a. (tryptophan, phenylalanine), peptides released by gastric proteolysis, acid pH, lipid and free fatty acids.
Name 2 functions of CCK.
CCK causes contraction of gallbladder to secrete bile acids and it stimulates the secretion of pancreatic enzymes from the pancreas.
The functional part of the hormone, gastrin and CCK resides in the __________ region of the peptide.
Last five a.a. of the C-terminus.
Name the secretion signal and the function of secretin.
Secretin is released in response to acidification (pH < 5) of the contents of the duodenum. Secretin works to stimulate the secretion of pancreatic juice rich in bicarbonate.
The major hormone that causes NaCl secretion is ____________.
VIP (vasoactive intestinal peptide).
Guanylin promotes the secretion of _____________.
NaCl.
GIP stimulates the secretion of _____________.
GIP stimulates insulin secretion.
Glucose stimulates the secretion of _____________.
GIP and therefore insulin.
