What triggers gastrin release and what is its primary effect on the stomach?

• A. Gastrin is released in response to fats and fatty acids; it inhibits parietal cells.
• B. Gastrin is released only during fasting and has no effect on mucosa.
• C. Gastrin is released in response to peptides, amino acids, and vagal stimulation; it stimulates parietal cells to secrete HCl and promotes mucosal growth.
• D. Gastrin is released by pyloric glands and has no effect on mucosal growth.

Answer: (C)

Gastrin release is triggered by the presence of peptides and amino acids in the stomach and by vagal stimulation. Its primary effect is to stimulate the parietal cells to secrete hydrochloric acid, raising gastric acidity, and to promote growth of the gastric mucosa. This dual action helps optimize digestion and maintain the lining of the stomach. Fats and fatty acids don’t primarily trigger gastrin; they stimulate other pathways (like CCK) and can slow gastric emptying. Gastrin is released by G cells in the pyloric region of the stomach, and its secretion is tempered by gastric acidity through feedback mechanisms.