Fiser Chapter 28 GUT HORMONES Flashcards
What cells produce:
- Gastrin
- Somatostatin
- CCK
- Secrein
- VIP
- Glucagon
- Insulin
- Pancreatic polypeptide
- Motilin
- Bombesin
- Gastrin: antral G cells
- Somatostain: antral D cells
- CCK: duodenal I cells
- Secretin: duodenal S cells
- VIP: gut and panc
- Glucagon: pancreas alpha cells
- Insulin: pancreas beta cells
- Pancreatic polypeptide: pancreas islet cells
- Motilin: intestinal cells
What stimulates and inhibits gastric release from antral G cells?
Stimulated by: amino acids, vagal input (ACh), Calcium, EtOH, Antral distension, pH > 3.0
Inhibits: pH<3.0, somatostain, secretin, CCK
Gastrin does what?
Acts on parietal and chief cells to increase HCL, IF, and pepsinogen activation
Omeprazole MoA
Blocks H/K ATPase of parietal cell (final pathway for H+ release)
What stimulates somatostatin release from antral D cells?
Acid in duodenum
What is the response to somatostatin?
Inhibits gastrin and HCL release
Inhibits release of insulin, glucagon, secretin, motilin
Decreases pancreatic and biliary output
What can be used to decrease pancreatic fistula output?
Ocreotide
What stimulates CCK release from duodenal I cells?
Amino acids and fatty acid chains
What is the response to CCK?
Gallbladder contraction, sphincter of Oddi relaxation, and pancreatic enzyme secretion
What stimulates and inhibits secretin release from duodenal S cells?
Stimulated by: fat, bile, pH<4.0
Inhibited by pH>4.0 and gastrin
What is the response to secretin?
Pancreatic bicarb release (decreased in chronic pancreatitis and end stage pancreatitis)
Inhibited gastrin release (reversed in gastrinoma)
Inhibited HCL release
Pancreatic Secretin Test
Normal 2ml/kg/hr, bicarb >10mmol/L/hr, amylase 6-18 IU/kg
- Chronic panc: decreased bicarb
- End stage panc: decreased all
- Malnutrition: decreased enzyme
Panc cancer: decreased volume
Zollinger-Ellision: increased volume
What stimulates VIP release?
Fat and ACh
What is the response to VIP?
Increased intestinal secretion (water and electrolytes) and motility
VIPoma
WDHA: watery diarrhea, hypokalemia, achlorhydria
What stimulates and inhibits
Stimulated by: low glucose, high amino acids, ACh
Inhibited by: glucose, insulin, somatostatin
Result of glucagon?
Glycogenolysis, gluconeogenesis, lipolysis, ketogenesis, decreased HCL, decreased GI motility, relaxes sphincter of Oddi
What stimulates and inhibits insulin?
Stimulated by: glucose, glucagons, CCK
Inhibited by: somatostatin
Response to insulin?
Cellular glucose uptake, promotes protein synthesis
What stimulates pancreatic polypeptide from panc islet cells?
Food, vagus, hormons
Pancreatic polypeptide response?
Decrased pancreatic and gallbladder secretion
What stimulates and inhibits motilin release by gut intestinal cells?
Stimulated by: duodenal acid, food, vagus
Inhibited by: somatostatin, secretin, pancreatic polypeptide, duodenal fat
Motilin response?
Increased motility (small bowel; phase III peristalsis) –> erythromycin acts here
Bombesin
Gastrin-releasing peptide (GRP)
Causes increased intestinal motor activity, increased pancreatic enzyme secretion, and increased gastric acid secretion
Peptide YY
Ileal break
Released from TI after a fatty meal
inhibits acid secretion and stomach contraction
Inhibits gallbladder contraction and pancreatic secretion
What mediates anorexia?
Hypothalamus
Bowel recovery order
Small bowel 24 hours
Stomach 48 hours
Large bowel 3-5 days
Enterokinase
Activates trypsinogen to trypsin -> activates other enzymes of digestion
MMC phases
Interdigestive motility; 90 min cycles; starts in stomach, goes to TI
I. quiescence
II. gallbladder contraction
III. peristalsis
IV. subsiding electric activity
Where is gastrin made?
antrum G cell
Where is somatostatin made?
antrum D cell
Where is CCK made?
duodenal I cell
Where is secretin made?
duodenal S cells
Where is VIP made?
Gut and pancreas cells
Where is glucagon made?
pancreatic Alpha cells
Where is insulin made?
pancreas Beta cells
Where is pancreatic polypeptide made?
Panc islet cells
Where is motilin made?
Intestinal cells
