gut hormones Flashcards
(18 cards)
neuronal signaling in GI tract
ANS delivers cholinergic and adrenergic signals from the CNS to the cells in the GI
peptides in the secretin family
- secretin
- vasoactive intestinal polypeptide (VIP)
- gastric inhibitory peptide (GIP)
- glucagon like peptide (GLP-1)
- Bombesin (GRP)
peptides in gastrin famiy
- gastrin
- CCK
- motilin
- enkaphalin
major physiological roles of gastrin
1 - stimulation of gastric acid from oxyntic cells
2- trophic action on the mucosa of the stomach
3 - stimulation of gastric motility
stimulators of gastrin
- peptide digestion products in chyme
- vagal activity through Bombesin and GRP
- AAs in chyme
- calcium in chyme
inhibitors of gastrin
- pH below 3.5
- release inhibited by secretin
- action inhibited by CCK
Zollinger-Ellison Syndrome (ZE)
- gastrin hypersecretion from gastrinomas
- leads to ulcerative disease
ZE diagnostic test
- give secretin
- secretin will conversely cause increase in circulating gastrin levels
CCK physiological effects
- HCO3-/H2O secretion (synergy with secretin)
- pancreatic enzyme secretion
- gallbladder contraction increasing flow of bile
- inhibits gastrin induced acid secretion
physiological effects of secretin
- bile HCO3-/H2O secretion
- pancreatic HCO3-/H2O secretion (synergy with CCK)
- inhibits gastrin which reduces acid secretion
CCK release stimulated by
- peptides and AAs in chyme (most important)
- fatty foods
secretin stimulated by
pH under 4.0 in duodenum
What is Bombesin?
- peptide made in neurons
- also called GRP
What does Bombesin do?
releases gastrin (vagal)
what receptor does leptin bind to?
Jak/Stat receptors
what is the most clinically important gut hormone?
GLP-1
What does GLP-1 do?
- causes insulin release before blood glucose increases
- inhibits glucagon release
relationship between GLP-1 and Type 2 DM
- GLP-1 is reduced in those with Type 2 DM
- GLP-1 is rapidly deactivated by a di-peptide peptidase (DPP4)
- treatment with gliptins inhibits DPP4
- also there is treatment with incretin mimetics (degradation-resistant GLP-1 receptor agonists)
