gut hormones

Question 1

neuronal signaling in GI tract

Answer 1

ANS delivers cholinergic and adrenergic signals from the CNS to the cells in the GI

Question 2

peptides in the secretin family

Answer 2

• secretin
• vasoactive intestinal polypeptide (VIP)
• gastric inhibitory peptide (GIP)
• glucagon like peptide (GLP-1)
• Bombesin (GRP)

Question 3

peptides in gastrin famiy

Answer 3

• gastrin
• CCK
• motilin
• enkaphalin

Question 4

major physiological roles of gastrin

Answer 4

1 - stimulation of gastric acid from oxyntic cells
2- trophic action on the mucosa of the stomach
3 - stimulation of gastric motility

Question 5

stimulators of gastrin

Answer 5

• peptide digestion products in chyme
• vagal activity through Bombesin and GRP
• AAs in chyme
• calcium in chyme

Question 6

inhibitors of gastrin

Answer 6

• pH below 3.5
• release inhibited by secretin
• action inhibited by CCK

Question 7

Zollinger-Ellison Syndrome (ZE)

Answer 7

• gastrin hypersecretion from gastrinomas

- leads to ulcerative disease

Question 8

ZE diagnostic test

Answer 8

• give secretin

- secretin will conversely cause increase in circulating gastrin levels

Question 9

CCK physiological effects

Answer 9

• HCO3-/H2O secretion (synergy with secretin)
• pancreatic enzyme secretion
• gallbladder contraction increasing flow of bile
• inhibits gastrin induced acid secretion

Question 10

physiological effects of secretin

Answer 10

• bile HCO3-/H2O secretion
• pancreatic HCO3-/H2O secretion (synergy with CCK)
• inhibits gastrin which reduces acid secretion

Question 11

CCK release stimulated by

Answer 11

• peptides and AAs in chyme (most important)

- fatty foods

Question 12

secretin stimulated by

Answer 12

pH under 4.0 in duodenum

Question 13

What is Bombesin?

Answer 13

• peptide made in neurons

- also called GRP

Question 14

What does Bombesin do?

Answer 14

releases gastrin (vagal)

Question 15

what receptor does leptin bind to?

Answer 15

Jak/Stat receptors

Question 16

what is the most clinically important gut hormone?

Answer 16

GLP-1

Question 17

What does GLP-1 do?

Answer 17

• causes insulin release before blood glucose increases

- inhibits glucagon release

Question 18

relationship between GLP-1 and Type 2 DM

Answer 18

• 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)