Question 2#

Which of the following inhibits gastrin secretion?

A) Histamine
B) Acetylcholine
C) Amino acids
D) Acid

Correct Answer is D


Luminal peptides and amino acids are the most potent stimulants of gastrin release, and luminal acid is the most potent inhibitor of gastrin secretion. The latter effect is predominantly mediated in a paracrine fashion by somatostatin released from antral D cells. Gastrin-stimulated acid secretion is significantly blocked by H2 antagonists, suggesting that the principal mediator of gastrin-stimulated acid production is histamine from mucosal enterochromaffin-like (ECL) cells. Acetylcholine released by the vagus nerve leads to stimulation ofECL cells, which in turn produce histamine.