Cholecystokinin (CCK)

Biochemistry and Synthesis
  • Cholecystokinin (CCK) is a peptide hormone secreted by I Cells present within the small intestine mucosa of the duodenum and jejunum.
CCK Regulation
  • CCK release is stimulated by the presence of fats, (specifically fatty acids) and small peptides or amino acids in the early small intestine. These stimuli are probably directly sensed by the I Cells which then release CCK into the blood stream.
CCK Actions
  • Overview
    • The overall effect of CCK is to promote fat and protein digestion in the small bowel through multiple, independent mechanisms of action.
  • Mechanisms of Action
    • Allows increased time for digestion of fats and proteins in the small intestine by inhibiting gastric emptying (See: Gastric Motility).
    • Promotes entry of fat digesting bile into the small intestine by inducing contraction of the gallbladder and relaxation of sphincter of Oddi.
    • Promotes the entry of fat and protein-digesting enzymes into the small intestine by enhancing pancreatic secretion.
    • Assists in long-term maintenance and health of organs critical for fat and protein digestion by inducing a trophic effect on the exocrine pancreas and gallbladder.