GI Hormones Flashcards
decrease gastric emptying
Cholecystokinin
secreted by I cells (duodenum, jejunum)
Cholecystokinin
this hormone secretion is inhibited when stomach pH < 1.5
gastrin
this hormone secretion is inhibited by vagal stimulation
somatostatin
pepsin secretion is upregulated by these 2 factors:
vagal stimulation, local acid
this hormone secretion is inhibited by adrenergic input
VIP
decrease insulin and glucagon release
Somatostatin
what is a VIPoma?
non-α, non-β islet cell pancreatic tumor that secretes VIP -> copious watery diarrhea -> Hypokalemia -> Achlorhydria WDHA syndrome
gastric acid secretion
upregulated by these 3 factors:
downregulated by these 4 factors:
up: Histamine***, ACh, Gastrin (via ECL cells -> histamine)
down: somatostatin, GIP, prostaglandin (misoprostol), secretin
secreted by Parasympathetic ganglia in sphincters, gallbladder, small intestine
VIP
increase gastric motility
Gastrin
decrease pepsinogen secretion
Somatostatin
increase smooth muscle relaxation, including lower esophageal sphincter (LES)
NO
Loss of NO secretion is implicated in increased LES tone of achalasia.
secreted by Small intestine
motilin
this hormone secretion is stimulated during fasting states
motilin
decrease gall bladder contraction
Somatostatin
increase relaxation of intestinal smooth muscle and sphincters
VIP
sphincter of Oddi relaxation
Cholecystokinin
decrease gastric H+ secretion
GIP, secretin, somatostatin
increase gallbladder contraction
Cholecystokinin
increase intestinal water and electrolyte secretion
VIP
Produces migrating motor complexes (MMCs)
Motilin
secreted by D cells (pancreatic islets, GI mucosa)
Somatostatin
decrease pancreatic and small intestine fluid secretion
Somatostatin
this hormone secretion is stimulated by stomach distention, alkalinization, a.a., peptides, vagal stimulation
gastrin
this hormone secretion is stimulated by FA + a.a.
cholecystokinin
secreted by S cells (duodenum)
Secretin
increase bile secretion
secretin
increase pancreatic HCO3– secretion
secretin
HCO3 neutralizes gastric acid in duodenum, allowing pancreatic enzymes to function.
this hormone secretion is stimulated by H+
secretin, somatostatin
increase insulin release
GIP
this hormone secretion is stimulated by distention and vagal stimulation
VIP
secreted by K cells (duodenum, jejunum)
Glucose-dependent insulinotropic peptide
increase gastric H+ secretion
Gastrin
secreted by G cells (antrum of stomach)
Gastrin
increase pancreatic secretion
Cholecystokinin
HCO3 secretion is upregulated by these 2 factors:
pancreatic and biliary secretion with secretin
motilin receptor agonist
erythromycin
this hormone secretion is stimulated by FA, a.a., oral glucose
GIP
increase growth of gastric mucosa
Gastrin
this hormone secretion is stimulated by H+, fatty acids in lumen of duodenum
secretin
potent stimulators of gastrin secretion
chronic PPI use (rebound acid secretion)
phenylalanine
tryptophan
Zollinger-Ellison Syndrome
of parietal cells
of G cells
acid secretion
secretin injection
# of parietal cells - increased because they are stimulated by gastrin to produce gastric acid + IF
# of G cells - decreased due to negative feedback from all the gastrin that is being produced by the tumor
acid secretion - increased; refractory to medical therapy
secretin injection –>increase gastrin secretion (paradoxical since secretin normally decreases it!!)
