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Endocrine · Reference monograph

Peptide inhibitor of multiple endocrine and exocrine secretions

Reference compound — not available from Purity Peptides. Shown for research context.

Overview

Somatostatin, also known as somatotropin release-inhibiting factor (SRIF), is a cyclic peptide hormone that exists in two principal forms: somatostatin-14 and the N-terminally extended somatostatin-28. Somatostatin-14 was isolated from ovine hypothalamus in 1973 by Paul Brazeau, Roger Guillemin and colleagues, who were searching for a growth hormone-releasing factor and instead found a potent inhibitor of growth hormone secretion.

Somatostatin is produced by hypothalamic neurons, pancreatic delta cells, gastrointestinal D-cells and many other cell types, and it acts as a broad inhibitor of endocrine and exocrine secretion. It suppresses growth hormone, thyroid-stimulating hormone, insulin, glucagon, gastrin and numerous other secretions, and it reduces splanchnic blood flow. Native somatostatin has a plasma half-life of only a few minutes, which limits its practical use and drove the design of stable analogues such as octreotide, lanreotide and pasireotide. Somatostatin itself is used in hospital settings in some jurisdictions but is not marketed in the United States. In research it is the reference ligand for SSTR1-5 receptor biology.

Mechanism studied

  1. Somatostatin
  2. SSTR1–5
  3. Hormone secretion ↓
  4. GH, insulin, glucagon

Somatostatin binds five receptor subtypes, SSTR1 through SSTR5, all class A G protein-coupled receptors coupled predominantly to Gi/o proteins. Receptor activation inhibits adenylyl cyclase and lowers cAMP, opens inwardly rectifying potassium channels to hyperpolarise cells, and inhibits voltage-gated calcium channels, together reducing hormone exocytosis. Some subtypes activate phosphotyrosine phosphatases such as SHP-1 and SHP-2 and modulate MAPK signalling, contributing to antiproliferative effects in cell models. Somatostatin-14 and somatostatin-28 bind all five subtypes with high affinity, although somatostatin-28 shows some preference for SSTR5. In islets, delta-cell somatostatin acts locally to restrain insulin and glucagon release.

Research highlights

  • 01Isolated in 1973 by Brazeau, Guillemin and colleagues; Guillemin shared the 1977 Nobel Prize for hypothalamic hormone research.
  • 02The five receptor subtypes were cloned in the early 1990s, enabling subtype-selective pharmacology.
  • 03Its short half-life led directly to the development of stable cyclic analogues used in neuroendocrine research.
  • 04Paracrine delta-cell signalling within islets is an active topic in research on glucagon dysregulation.
  • 05Open questions include SSTR heterodimerisation, biased signalling and the functions of somatostatin interneurons in cortical circuits.

Latest published research

35,566 papers on PubMed →

  1. Therapeutic hypothermia does not prevent dysmaturity of medial ganglionic eminence-derived interneurons in the dorsal hippocampus after neonatal hypoxia-ischemia

    Spahic H et al. · Experimental neurology · 2027 Jan · PMID 42679940

  2. Glycine transporter 1 inhibitor, bitopertin, changes excitatory and inhibitory network connectivity in mouse medial prefrontal cortex

    Graf M et al. · Neuropharmacology · 2026 Dec 15 · PMID 42722103

  3. Prevention and management of hormonal crisis in neuroendocrine tumors undergoing PRRT (peptide receptor radionuclide therapy): a systematic review

    Arrivi G et al. · ESMO gastrointestinal oncology · 2026 Dec · PMID 42927326

  4. Risk-adapted imaging of gastric neuroendocrine neoplasms: an entity-, type-, and grade-informed framework for staging and management

    Liu Y et al. · European journal of radiology · 2026 Dec · PMID 42800237

  5. Potential of sweetener substitutes to circumvent metabolic dysfunction-associated steatotic liver disease and hepatic fibrosis risk: Integrating network toxicology and validation in vitro

    Cheng Z et al. · Food and chemical toxicology : an international journal published for the British Industrial Biological Research Association · 2026 Dec · PMID 42732869

  6. Expression of Concern: The effects of somatostatin in the polycystic ovary syndrome

    Journal of obstetrics and gynaecology : the journal of the Institute of Obstetrics and Gynaecology · 2026 Dec · PMID 42725691

  7. Pancreatic islets: new discoveries for innovative treatments of diabetes?

    Scharfmann R et al. · Diabetologia · 2026 Dec · PMID 42627374

  8. Focal ischemic stroke impairs REM sleep and inhibits c-Fos expression of SST neuron in EP of male rats

    Xiong YQ et al. · Experimental neurology · 2026 Dec · PMID 42617907

Live feed from PubMed (NCBI) for “Somatostatin”, updated 2026-10-30. Listing a paper is not an endorsement of its findings.

Registered studies

362 on ClinicalTrials.gov →

From the public ClinicalTrials.gov registry for “Somatostatin”, updated 2026-10-30. Shown for research context only; Purity Peptides products are not for human use.

Key references

  1. [1]Manufacturer's prescribing information — FDA / EMA / ANVISA
  2. [2]PubMed — reviews on somatostatin and variceal bleeding

FAQ

  • It was discovered as a hypothalamic factor that inhibited release of growth hormone, also called somatotropin, from the pituitary. Researchers subsequently found that it inhibits many other hormones and secretions, but the original name reflecting its first identified action was retained.

  • There are five subtypes, SSTR1 to SSTR5. They differ in tissue distribution, signalling and analogue affinity. SSTR2 is the dominant subtype in many neuroendocrine tumours and is the main target of octreotide and lanreotide, while SSTR5 is important in corticotroph and beta-cell biology.

  • Native somatostatin is degraded within minutes, and its broad receptor activity produces widespread effects. Analogues such as octreotide were engineered with D-amino acids and a smaller cyclic structure to resist degradation and provide greater receptor selectivity for research and clinical applications.

FOR RESEARCH USE ONLY.Not for human or veterinary use. Not intended to diagnose, treat, cure, or prevent any disease.

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