| [ Summary ] |
Five somatostatin receptor(sst1-5) subtypes have been cloned. Sst subtypes are widely expressed In various tissues and cell types of the GI tract and the pancreas. Experiments, including those using sst2 knockout mice, showed that the sst2 mediates endogenous somatostatin-dependent inhibition of gastric acid secretion. Sst subtypes are also expressed in pancreatic endocrine tumors, carcinoids, and some pancreatic and colorectal cancers. Octreotide, a long acting synthetic somatostatin analogue, is effective in reducing symptoms caused by the hormones released from tumors. Somatostatin receptor scintigraphy, using somatostatin agonists is useful as a tumor-localizing technique in pancreatic endocrine tumors and carcinoids. |