I cells in the duodenum and jejunum secrete which hormone?

I cells in the duodenum and jejunum secrete cholecystokinin (CCK), which plays a crucial role in the digestive process. When fats and proteins enter the small intestine, CCK is released in response to these nutrients.

CCK stimulates the gallbladder to contract and release bile, which is important for the emulsification and digestion of fats. Additionally, it prompts the pancreas to secrete digestive enzymes, facilitating the breakdown of proteins and fats into smaller molecules absorbable by the intestines. Furthermore, CCK helps regulate satiety by sending signals to the brain, making the individual feel full after a meal.

This hormone is pivotal for coordinating the digestive process and ensuring that the body effectively absorbs nutrients from the food we eat, particularly in the early stages of digestion that occur in the duodenum and jejunum.