General Abdomen: GI Hormones
Hormones of the Stomach
Gastrin
- Secretion: Stomach G Cells Mn
- Stimulation: Amino Acid (Most Potent), Alkaline Environment & ACh (Vagus)
- Inhibition: HCl (Negative Feedback)
- Function: Stimulates Parietal & Chief Cells Mn
- Secretion: Stomach D Cells Mn
- Stimulated By: Acid in Duodenum
- Function: Inhibits Parietal Cells #1, Decreases Gastric Emptying & Inhibits Pancreatic/Biliary Output
- “The Great Inhibitor” Mn
- Octreotide – SS Analog
- Secretion: Stomach & Duodenum
- Function: Stimulate Hunger
Hormones of the Small Intestine
Cholecystokinin (CCK)
- Secretion: Duodenum I Cells Mn
- Stimulation: Amino Acids & Fatty Acids
- Function: Gallbladder Contraction, Sphincter of Oddi Relaxation & Pancreas Enzyme Secretion
- Secretion: Duodenum S Cells Mn
- Stimulation: Acid, Fat & Bile
- Function: Increase Pancreas HCO3 Secretion & Bile Secretion Mn
- Inhibits Gastrin & Parietal Cells
- Secretion: Duodenum
- Stimulation: Food & Acid
- Function: Increases Motility (Primarily in Stomach Antrum)
- Where Erythromycin Acts
- Also Known As: Glucose-Dependent Insulinotropic Polypeptide
- Secretion: Duodenum
- Stimulation: Glucose in Duodenum
- Function: Insulin Secretion (Primary Function) & Weak Gastric Acid Inhibitor
- Secretion: Terminal Ileum
- Stimulation: Fatty Meal
- Function: Inhibits Stomach, GB Contraction & Pancreas Secretion
Mnemonics
Secreting Cells
- G-G: G Cells Secrete Gastrin
- D (Double–SS): D Cells Secrete Somatostatin
- S (Single-S): S Cells Secrete Secretin
- I-CCK (“Icky”): I Cells Secrete CCK
Gastrin Function
- Gastrin-Gastric: Gastrin Stimulates Gastric Specific Functions
Somatostatin Function
- Somato-Statin = “Stasis” Stops All
CCK vs Secretin Effects
- “B.S.”: Bicarb/Bile from Secretin