Which gastrointestinal hormone stimulates insulin secretion by the pancreas?

Gastric Inhibitory Peptide (GIP) is the gastrointestinal hormone that plays a significant role in stimulating insulin secretion by the pancreas. GIP is secreted by the K cells in the duodenum and jejunum in response to the ingestion of carbohydrates and fats. Its primary function is to enhance the insulin response following a meal, thus promoting glucose uptake by tissues and helping in maintaining blood sugar levels.

This hormone acts by binding to specific receptors on the pancreatic beta cells, leading to an increase in the secretion of insulin. Insulin is crucial for glucose metabolism, and the action of GIP is part of the body's intricate feedback system that regulates blood glucose levels. This presents a coordinated response to food intake, allowing for proper homeostasis and the avoidance of postprandial hyperglycemia.

The other hormones listed have different effects: CCK (cholecystokinin) primarily stimulates gallbladder contraction and pancreatic enzyme secretion but does not directly stimulate insulin secretion. Secretin mainly promotes bicarbonate secretion from the pancreas to neutralize gastric acid in the small intestine, while gastrin primarily stimulates gastric acid secretion and does not have a direct role in insulin regulation. Thus, the role of GIP as a stimulator of insulin secretion