PMID-10433861 – Somatostatin and Its Receptor Family
Patel YC. "Somatostatin and its receptor family," Front Neuroendocrinol, 1999;20(3):157-198.
Quick Reference
| Property | Value |
|---|---|
| PMID | 10433861 |
| DOI | 10.1006/frne.1999.0183 |
| Year | 1999 |
| Journal | Frontiers in Neuroendocrinology |
| Study Type | Narrative Review |
| Evidence Level | V |
| Sample | N/A (review) |
| Peptide(s) Studied | Somatostatin |
Key Findings
- Somatostatin exists in two bioactive forms: SST-14 (cyclic 14-aa) and SST-28 (N-terminally extended 28-aa), both processed from preprosomatostatin (116 aa)
- Five somatostatin receptor subtypes (SSTR1-5) have been cloned, all G-protein coupled receptors coupling to Gi/Go
- All five SSTRs inhibit adenylyl cyclase; SSTR2 and SSTR5 are the most pharmacologically important
- SSTR2 mediates most of somatostatin's inhibitory effects on GH, TSH, and gastric acid
- SSTR5 is preferentially activated by SST-28 and mediates insulin inhibition
- Somatostatin is produced by: hypothalamus (neuroendocrine), pancreatic delta cells, GI D cells, thyroid C cells, and neurons throughout the CNS
- Functions as the "universal inhibitor": suppresses GH, TSH, insulin, glucagon, gastric acid, pancreatic enzymes, bile flow, intestinal motility, and multiple immune functions
- Very short half-life (~3 minutes) due to rapid enzymatic degradation — this limitation drove development of somatostatin analogs (octreotide, lanreotide, pasireotide)
Study Design
Comprehensive review covering somatostatin molecular biology, receptor pharmacology, signal transduction, tissue distribution, physiological functions, and pathophysiological roles. Integrates data from molecular cloning, binding studies, knockout mice, and clinical observations.
Limitations
- Published 1999; predates full understanding of SSTR signaling complexity and some receptor interactions
- Does not cover PRRT (peptide receptor radionuclide therapy) which emerged later
- Crystal structures of SSTRs were not available at time of publication
Clinical Relevance
This foundational review explains why native somatostatin cannot be used therapeutically (3-minute half-life) and how understanding SSTR subtype selectivity guided development of clinically successful analogs: octreotide (SSTR2/SSTR5 selective), lanreotide (SSTR2 selective), and pasireotide (pan-SSTR with SSTR5 preference). For the vault, this note provides essential context for the entire Somatostatin Analogs & PRRT category and explains the pharmacological rationale behind each analog's receptor selectivity profile.
Related
#research #narrative-review #evidence-level-V #gh-axis #somatostatin #endogenous