PMID-16625838 – Physiology of Somatostatin Receptors
Cervia D, Bhatt DK, Bhatt DK. "Physiology of somatostatin receptors," Eur J Endocrinol, 2006;156 Suppl 1:S13-S20.
Quick Reference
| Property | Value |
|---|---|
| PMID | 16625838 |
| DOI | 10.1530/eje.1.02352 |
| Year | 2006 |
| Journal | European Journal of Endocrinology |
| Study Type | Narrative Review |
| Evidence Level | V |
| Sample | N/A (review) |
| Peptide(s) Studied | Somatostatin |
Key Findings
- SSTR1-5 share common signaling: all inhibit adenylyl cyclase via Gi proteins, activate phosphotyrosine phosphatase (PTP), and modulate MAPK
- SSTR2 exists in two splice variants (SSTR2A and SSTR2B) with different C-terminal tails affecting internalization and desensitization
- SSTR2 mediates the majority of GH inhibition in the pituitary — explaining why octreotide (SSTR2/5 agonist) is effective for acromegaly
- SSTR5 is the primary mediator of insulin and glucagon suppression in pancreatic islets
- SSTR1 and SSTR4 do not internalize upon agonist binding (unlike SSTR2, 3, 5), which has implications for sustained signaling
- SSTR3 activates apoptotic pathways — potentially relevant for antitumor effects
- SSTRs form homo- and heterodimers (e.g., SSTR2-SSTR5 heterodimers in pituitary), which modulates receptor pharmacology
- Receptor density varies by tissue: pituitary (SSTR2, SSTR5), pancreas (SSTR2, SSTR5), GI tract (SSTR2), brain (SSTR2, SSTR4)
Study Design
Focused review of somatostatin receptor physiology covering signal transduction, receptor trafficking, dimerization, tissue-specific expression, and functional consequences for endocrine regulation.
Limitations
- Review article; no new primary data
- Published 2006; additional receptor crystal structure and signaling data available since
- Limited coverage of SSTR roles in immune system and CNS
Clinical Relevance
Understanding SSTR subtype physiology is essential for rational use of somatostatin analogs. The differential expression of SSTR subtypes explains why: (1) octreotide works well for acromegaly (pituitary has SSTR2) and carcinoid (SSTR2+ tumors), (2) pasireotide (SSTR5-preferring) works for Cushing's disease where SSTR2 expression may be lower, and (3) PRRT with Lu-177-DOTATATE targets SSTR2+ neuroendocrine tumors. For peptide therapy education, this note explains the receptor basis for drug design across the somatostatin analog class.
Related
#research #narrative-review #evidence-level-V #gh-axis #somatostatin #endogenous