GI: Hormones and Actions Flashcards
Gastrin
endocrine hormone
Secretion Site: G-cells (Gastric Antrum)
Stimuli for secretion: Small peptides and AA
Action: *Increase parietal cell activity (H+ secretion)
*Increase ECL cell activity (Histamine secretion
which acts on parietal cells to increase H+
secretion).
*Increase growth of gastric mucosa (protection
against increased acid secretion in stomach)
Cholecystokinin (CCK)
Paracrine and Endocrine hormone
Secretion Site: I- cells (duodenum)
Stimuli for secretion: Fatty acids, hydrolyzed proteins
Action: * Decreases gastric emptying and H+ secretion
(decreased gastric emptying helps provide the
time for absorption in the small intestine).
* Decreases food intake
* Increases pancreatic enzyme secretion
* Increased contraction of the gallbladder
* Relaxes sphincter of oddi
Secretin
Paracrine and Endocrine hormone
Secretion site: S-cells (duodenum)
Stimuli for secretion: H+ protons in duodenum
Action: * Increased pancreatic ductal secretion (H20 and
bicarb
GIP (glucoinsulinotropic peptide)
Endocrine Hormone
Secretion site: K-cells of duodenum and jejunum
Stimuli for secretion: Fatty acids and glucose
Actions: * Increased insulin secretion from pancreatic
beta cells).
Peptide YY (PYY)
Paracrine and Endocrine Hormone
Secretion site: L-cells of intestine
Stimuli for secretion: Fatty acids, glucose, hydrolyzed
proteins
Action: * decrease gastric emptying and acid secretions
* decreased pancreatic secretions
* decreased intestinal motility
* decreased food intake
Proglucagon-derived peptides 1/2 (GLP-1/2)
Paracrine and Endocrine Hormone
Secretion site: L-cells of intestine
Stimuli for secretion: Fatty acids, glucose, hydrolyzed
proteins
Action: * Glucose homeostasis
* Increased epithelial cell proliferation
Histamine
Paracrine Hormone
Secretion site: Enterochromaffin-like cells (ECL) in stomach
stimuli for secretion: Vagus (distent of stomach) acts on ENS and stimulates secretion
Action: * Binds to neighboring parietal cells that secrete HCL.
