cholecystokkinin

Cholecystokinin, often abbreviated as CCK or CCK-PZ, is a peptide hormone produced by I cells in the duodenum and jejunum, the first two sections of the small intestine. It is also found in neurons in the brain and gastrointestinal tract. CCK plays a significant role in digestion and satiety.

When food, particularly fats and proteins, enters the duodenum, it stimulates the release of CCK into the bloodstream. In the digestive system, CCK's primary functions are to stimulate the contraction of the gallbladder, releasing bile into the small intestine to aid in fat digestion and absorption. It also promotes the secretion of pancreatic enzymes from the pancreas, which are crucial for breaking down carbohydrates, proteins, and fats. Furthermore, CCK slows down gastric emptying, allowing more time for digestion and nutrient absorption in the small intestine.

Beyond its digestive roles, CCK acts as a satiety hormone. It signals to the brain, specifically to the hypothalamus, to induce feelings of fullness and reduce appetite. This neuroendocrine function contributes to the regulation of food intake and body weight. Research also suggests CCK has neuromodulatory effects in the central nervous system, influencing anxiety, pain perception, and learning and memory.