Search results
Results from the WOW.Com Content Network
Gastrin is a linear peptide hormone produced by G cells of the duodenum and in the pyloric antrum of the stomach.It is secreted into the bloodstream. The encoded polypeptide is preprogastrin, which is cleaved by enzymes in posttranslational modification to produce progastrin (an intermediate, inactive precursor) and then gastrin in various forms, primarily the following three:
As discussed earlier gastrin stimulates by activating parietal cells and stimulating ECL to produce histamine (histamine stimulates parietal cells to produce acid). [2] Small peptides also buffer stomach acid so the pH does not fall excessively low. Gastric secretion is stimulated chiefly by three chemicals: acetylcholine (ACh), histamine, and ...
Gastrin itself has no effect on the maximum histamine-stimulated gastric acid secretion. [7] The effect of histamine, acetylcholine and gastrin is synergistic, that is, effect of two simultaneously is more than additive of effect of the two individually. It helps in non-linear increase of secretion with stimuli physiologically. [8]
Gastrin acts on parietal cells directly and indirectly too, by stimulating the release of histamine. The release of histamine is the most important positive regulation mechanism of the secretion of gastric acid in the stomach. Its release is stimulated by gastrin and acetylcholine and inhibited by somatostatin. [11]
These cells are stimulated by the hormones gastrin (not depicted in the adjacent diagram) and pituitary adenylyl cyclase-activating peptide. G cells are stimulated by vagal stimulation through the neurotransmitter gastrin-releasing peptide ; this causes the G cells to secrete gastrin, which in turn stimulates ECL cells to release histamine.
Little gastrin: 2098: 17: Both forms of gastrin are found in the gastric antrum and duodenum: Gastrins stimulate the secretion of gastric acid, pepsinogen, intrinsic factor, and secretin; stimulate intestinal mucosal growth; increase gastric and intestinal motility Big gastrin: 3839: 34: Secretin-glucagon family: Secretin: 3056: 27: Duodenum ...
A G cell or gastrin cell is a type of cell in the stomach and duodenum that secretes gastrin. It works in conjunction with gastric chief cells and parietal cells. G cells are found deep within the pyloric glands of the stomach antrum, and occasionally in the pancreas [1] and duodenum. The vagus nerve innervates the G cells.
Inhibition of gastrin and gastric acid secretion is lifted. This triggers G cells to release gastrin, which in turn stimulates parietal cells to secrete gastric acid. Gastric acid is about 0.5% hydrochloric acid, which lowers the pH to the desired pH of 1–3. Acid release is also triggered by acetylcholine and histamine.