Geri

Gastrin – The Hormone of Digestive Regulation

Gastrin (from the Greek gaster – "stomach") is a hormone that regulates digestion by stimulating the secretion of gastric acid (HCl) and digestive enzymes. It is produced by G-cells, which are part of the diffuse endocrine system of the gastrointestinal tract, mainly located in the stomach lining, duodenum, and pancreas.
 

✔ Stimulates gastric acid (HCl) production – Activates parietal cells in the stomach to release hydrochloric acid, which helps digest food.
✔ Enhances digestive enzyme secretion – Stimulates pancreatic enzyme release for protein and fat digestion.
✔ Promotes bile production – Helps break down fats.
✔ Regulates stomach motility – Ensures food moves properly through the GI tract.
✔ Supports gut cell growth – Helps maintain the gastric and intestinal lining.

Gastrin secretion increases in response to:

  • Protein-rich food.
  • Stomach wall distension (after eating).
  • Reduced stomach acidity.

Gastrin secretion decreases when:

  • Acid levels rise (negative feedback mechanism).
  • Digestion is complete.

     
  • Avoid alcohol for 24 hours before testing.
  • Limit fatty foods for 24 hours before testing.
  • Avoid caffeine-containing foods for 8 hours before testing.
  • Reduce physical and emotional stress before the test.
  • Do not smoke for at least 1 hour before the test.
  • Vitamin B12 Deficiency Symptoms – Includes anemia, epithelial damage, intestinal issues, and neurological disorders.
  • Peptic Ulcers – Persistent or recurrent ulcers in the stomach or duodenum.
  • Wermer Syndrome – Multiple endocrine neoplasia affecting the digestive system.
  • Zollinger-Ellison Syndrome – Characterized by gastrin-secreting tumors (gastrinomas), leading to excessive gastric acid production and recurrent ulcers.
  • Addison-Biermer Disease (Pernicious Anemia) – Increased gastrin levels due to reduced Castle’s intrinsic factor, which impairs vitamin B12 absorption and damages the stomach lining.

 Elevated Gastrin Levels May Indicate:

  • Gastric tumors (gastrinomas).
  • Chronic atrophic gastritis (stomach lining inflammation).
  • Megaloblastic anemia (B12 deficiency anemia).
  • Zollinger-Ellison Syndrome – Excessive gastrin production due to tumors.
  • Addison-Biermer Disease (Pernicious Anemia) – Associated with severe vitamin B12 deficiency.

Reduced Gastrin Levels May Indicate:

  • Hyperthyroidism (overactive thyroid).
  • Atropine or secretin administration (both inhibit gastrin production).