MRCP UK EXAMINATIONS

ABDOMINAL

GASTROINTESTINAL

Question [CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
What is the main stimulant for HCl secretion and what is the main inhibitor?
A
gastrin and somatostatin
B
acetylcholine and leptins
C
Histamine and somatostatin
D
None of the above
Explanation: 

Detailed explanation-1: -Gastrin is a peptide hormone primarily responsible for enhancing gastric mucosal growth, gastric motility, and secretion of hydrochloric acid (HCl) into the stomach.

Detailed explanation-2: -The main stimulants of acid secretion are gastrin, released from antral G cells; histamine, released from oxyntic enterochromaffin-like cells; and acetylcholine, released from antral and oxyntic intramural neurons. Other stimulants include ghrelin, motilin, and hydrogen sulfide.

Detailed explanation-3: -Somatostatin is a potent inhibitor of gastrin-stimulated acid secretion by activation of somatostatin receptor type 2 (sst2) in vivo, probably in part by blocking gastrin-stimulated histamine release from enterochromaffin-like cells expressing sst2.

Detailed explanation-4: -Gastrin is a peptide hormone that stimulates secretion of gastric acid (HCl) by the parietal cells of the stomach and aids in gastric motility. It is released by G cells in the pyloric antrum of the stomach, duodenum, and the pancreas.

Detailed explanation-5: -Somatostatin is present in the gut and acts to decrease acid secretion. The hormone gastrin is released, in a feedback fashion, when the antrum is alkalinized. Most stimuli of acid secretion are blocked by H2-antagonists.

There is 1 question to complete.