From the Guidelines
Cholecystokinin (CCK) is primarily produced in the proximal small bowel. This production is supported by the study published in the Clinical Gastroenterology and Hepatology journal in 2011 1. The key points related to CCK production and function include:
- CCK is a 33 amino acid polypeptide hormone
- It is stimulated to be released into the blood after ingestion of a meal
- CCK binds to receptors in the gallbladder causing contraction and receptors on the inhibitory neurons innervating the sphincter of Oddi causing relaxation leading to increased bile flow into the intestine The production of CCK in the small bowel is crucial for its role in controlling gallbladder emptying and other gastrointestinal effects. Some of the other effects of CCK include:
- Inhibition of gastric emptying
- Suppression of appetite
- Increased intestinal peristalsis These effects highlight the importance of CCK in maintaining proper physiological balance in the body, particularly in relation to digestion and appetite regulation.
From the Research
Location of Cholecystokinin (CCK) Production
- CCK is produced by the enteroendocrine I-cells in the upper part of the small intestine 2
- CCK cells are concentrated in the proximal small intestine 3
- The general notion is that I cells are present mainly in the proximal small intestine 4
- A gradual decrease in CCK mRNA expression and density of CCK-immunoreactive cells is observed from duodenum to ileum 4
- Very few CCK-immunoreactive cells and nearly undetectable CCK mRNA expression are found in the large intestine 4
Regulation of CCK Secretion
- Ingestion of fat and protein induces significant increases in plasma CCK 5
- Carbohydrates stimulate only small amounts of CCK release 2
- CCK secretion is regulated by intraluminal mediators, including luminal CCK releasing factor and diazepam-binding inhibitor 5
- Bile exclusion from the duodenum causes an increase in basal CCK and enhances stimulated plasma CCK release 5