GI hormones

Question 1

Gut hormone types

Answer 1

Peptides, released by exocytosis
From enteroendocrine cells, electrically active and fire AP in response to presence of digested food in GI tract
Short half life, inactivated by peptidases

Question 2

Histamine

Answer 2

Secreted from stomach
Increase acid secretion via H2 receptors
enterochromaffin like cells (ECL)of stomach wall
release: vagal stimulation
paracrine action

Question 3

Gastrin

Answer 3

From G cells 
Gastric acid secretion
From protein digestion products, vagus with ACh, distension with stomach
Insertion of pump into cell
inhibited by low pH and somatostatin

Question 4

Secretin

Answer 4

From duodenum S cells
Stimulated by acid in proximal duodenum
Stimulate pancreatic secretion of bicarbonate and water, stimulated liver secretion of bicarbonate and water into bile

Question 5

Somatostatin

Answer 5

Inhibit secretions and other hormone release
local inhibition/ negative feedback
acts at Gi
Paracrine

Question 6

VIP

Answer 6

Vasodilator, aids absorption
Work with NO to decrease motility
mostly in colon

Question 7

CCK

Answer 7

Stimulates secretion of pancreatic enzymes and bile from gall bladder contraction
Released stimulated by fats and proteins
produced in duodenum and jejunum 
signals satiety, suppresses appetite
Produced in duodenum

Question 8

Enkephalins

Answer 8

Increase gut motility

Question 9

Ghrelin

Answer 9

From stomach, hunger hormone and increase appetitie

from stomach

Question 10

GLP1 and GIP

Answer 10

both from small intestine
stimulated by meals
potentiates glucose stimulated insulin release

Question 11

two families of gut hormones

Answer 11

gastrin -like eg. CCK, act by IP3 pathway and increase calcium
secretin-like eg. glucagon, act by cAMP pathway