From the Research
Yes, somatostatin decreases cholecystokinin (CCK) secretion. Somatostatin is a regulatory peptide hormone that acts as a general inhibitor of numerous gastrointestinal functions, including the release of various gut hormones. When somatostatin is released or administered, it binds to somatostatin receptors on CCK-producing cells in the small intestine, particularly in the duodenum and jejunum, and inhibits their secretory activity. This inhibitory effect occurs through multiple cellular mechanisms, including inhibition of calcium influx and reduction of cyclic AMP levels within the CCK-producing cells, which ultimately prevents the release of CCK.
Mechanism of Action
The mechanism by which somatostatin inhibits CCK secretion is complex and involves the inhibition of the secretion and action of a CCK-releasing peptide (CCK-RP) secreted from the small intestine, as demonstrated by studies such as 1. This study showed that intravenous infusion of somatostatin completely inhibited the increase in amylase output evoked by diversion of bile-pancreatic juice and 80% of the increase in plasma CCK. Furthermore, the inhibitory action of somatostatin on CCK release evoked by CCK-RP was antagonized by pretreatment with pertussis toxin, suggesting a role for G-protein coupled receptors in this process.
Clinical Implications
Clinically, synthetic somatostatin analogs like octreotide can be used to reduce hormone secretion in conditions where excessive gut hormone production occurs. However, the effectiveness of somatostatin or its analogs in treating conditions such as acute or chronic pancreatitis is still controversial, with some studies showing no benefit 2, while others suggest a potential role in reducing complications in specific settings, such as elective pancreatic surgery.
Evidence Summary
The evidence from various studies, including those on the expression of somatostatin receptors in pancreatic cancer cells 3 and the regulation of duodenal CCK and somatostatin mRNA by somatostatin 4, supports the role of somatostatin in inhibiting CCK secretion. Additionally, studies on the effect of cholecystokinin and secretin on somatostatin release from cultured antral cells 5 provide further insights into the complex regulatory network controlling digestive processes.
Key Points
- Somatostatin inhibits CCK secretion through multiple mechanisms.
- The inhibition of CCK-RP secretion and action is a key mechanism by which somatostatin exerts its effects.
- Synthetic somatostatin analogs like octreotide can be used clinically to reduce hormone secretion.
- The effectiveness of somatostatin or its analogs in treating certain conditions, such as pancreatitis, is still controversial and requires further study.