What hormone is secreted by G cells to increase gastric motility?

G cells are specialized endocrine cells located in the stomach lining that primarily secrete gastrin, a hormone crucial for regulating gastric function. Gastrin plays a significant role in increasing gastric motility, which is the movement of the stomach muscles to mix and propel its contents.

When food enters the stomach, G cells release gastrin into the bloodstream, which then acts on different targets, including parietal cells to stimulate acid secretion, and smooth muscle cells to enhance motility. This increased motility aids in mixing the gastric contents and promoting the digestive process, allowing for better breakdown of food and preparation for further digestion in the intestines.

While histamine and acetylcholine also have roles in regulating gastric functions, they do not originate from G cells, nor are they directly responsible for increasing gastric motility like gastrin does. Pepsin is an enzyme involved in the digestion of proteins but is not a hormone nor does it directly influence gastric motility. Thus, gastrin is the correct hormone associated with enhancing gastric motility.