Which hormone stimulates gastric glands to secrete substances in the stomach?

Gastrin is the hormone responsible for stimulating gastric glands to secrete various substances in the stomach. Primarily produced by G cells in the gastric mucosa, gastrin is released in response to the presence of food in the stomach. It stimulates the secretion of gastric acid (HCl) from parietal cells and promotes the release of pepsinogen from chief cells, both of which are crucial for the digestion of proteins. Furthermore, gastrin enhances gastric motility, thereby facilitating the movement of food through the gastrointestinal tract.

In contrast, the other hormones listed have different roles in digestion. Secretin primarily regulates the pH of the small intestine by stimulating the pancreas to secrete bicarbonate-rich fluid, while cholecystokinin is involved in stimulating the gallbladder to release bile and the pancreas to release digestive enzymes in response to fats and proteins in the duodenum. Insulin, produced by the pancreas, plays a critical role in glucose metabolism and does not have a direct effect on gastric gland secretions. Understanding the specific functions of each hormone is vital for comprehending the complex regulation of digestive processes.