Cholecystokinin, Previously known as pancreozymin, is a peptide hormone of the gastrointestinal system responsible for stimulating the digestion of fat and protein. Cholecystokinin (CCK) is secreted by the duodenum (the first part of the small intestine) and causes the release of digestive
enzymes from the pancreas and bile from the gall bladder. It also acts
as a hunger suppressant. Recent evidence has suggested that it plays a major
role in inducing drug tolerance to opioids like morphine and heroin, and
is partly responsible for the pain hypersensitivity often experienced during
| Cholecystokinin molecule.