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Somatostatin, also called growth hormone-inhibiting hormone, is a cyclic peptide that acts as a widespread inhibitory signal, dampening the release of growth hormone, insulin, glucagon, and gastrointestinal secretions. It operates through five G-protein-coupled receptor subtypes (SSTR1 to SSTR5) that couple mainly to inhibition of adenylate cyclase and cyclic AMP, with additional signaling through ion channels and downstream kinases; notably, some subtypes such as SSTR3 exert constitutive, ligand-independent suppression of growth hormone synthesis. Its very short half-life in the circulation spurred the development of longer-acting analogues such as octreotide and lanreotide, which selectively target SSTR2 and SSTR5 to treat acromegaly and neuroendocrine tumors. The same gene also yields the related peptide neuronostatin, underscoring the system's role as a finely tuned regulator of endocrine and metabolic tone.
- Suppresses excess growth hormone
- Controls certain hormone-secreting tumors
- Reduces splanchnic blood flow in bleeding
- Broad hormone regulation
- The body's broad brake on hormone secretion
- can raise or lower blood sugar by suppressing both insulin and glucagon
- gastrointestinal effects such as nausea, cramping, or loose stools
- gallstones with long-term analog use, from reduced gallbladder emptying
Overview
Somatostatin is a small regulatory peptide hormone, widely known as growth hormone-inhibiting hormone. It occurs in two active forms, a fourteen-amino-acid version and a longer twenty-eight-amino-acid version, both cut from a single larger precursor protein. In broad terms it acts as an off switch for secretion, damping the output of numerous hormones and slowing several processes in the digestive tract [3].
The hormone is produced in many locations. In the brain it is made by neurons in regions including the hypothalamus and hippocampus, where it also behaves as a neuromodulator affecting neurotransmission and cognitive and motor functions [3]. Elsewhere it is secreted by specialized delta cells in the pancreatic islets and in the lining of the stomach and intestine, positioning it to regulate digestion and metabolism [3].
Its physiological effects are wide-ranging and predominantly inhibitory. In the pituitary gland it blocks the release of growth hormone and reduces thyroid-stimulating hormone and prolactin. In the pancreas and gut it suppresses the secretion of insulin, glucagon, gastric acid, and digestive enzymes, slows the emptying of the stomach, and reduces intestinal blood flow and motility [3]. It also restrains the proliferation of cells, an action that has drawn interest in cancer biology [3].
Somatostatin was first identified in the early 1970s as a factor from the hypothalamus that inhibits growth hormone release. Natural somatostatin is cleared from the blood within a few minutes, which limits its direct use as a drug. This led to the design of longer-acting synthetic analogs, notably octreotide, lanreotide, and pasireotide, which retain the inhibitory actions but persist far longer in the body [1]. These somatostatin receptor ligands are now standard treatments for acromegaly, a condition of growth hormone excess, and for hormone-secreting neuroendocrine tumors of the pancreas and gut, where they control symptoms and can slow tumor growth [1][2]. Radiolabeled analogs are also used to locate and treat such tumors [2].
Mechanism
Somatostatin works by binding to a family of five G-protein-coupled receptors, designated somatostatin receptors 1 through 5, that are distributed across the brain, pituitary, pancreas, gut, and many tumors [3]. Activation of these receptors generally lowers signaling inside the target cell, chiefly by reducing cyclic AMP and altering ion channels, which suppresses the release of hormones and other secretory products [3]. In tumor cells, receptor activation can also block growth-promoting signals and, in some cases, trigger programmed cell death, effects that underlie the antitumor use of its analogs [3]. Because the receptor subtype most commonly expressed on endocrine tumors is somatostatin receptor 2, synthetic drugs are designed to bind strongly to it [1][3].
receptor fingerprint
Somatostatin receptors SST1-5agonist
Growth hormone releaseinhibits
and glucagoninhibits
Gut hormones and motilityinhibits
Dosingtypical ranges, not medical advice
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Safetyrisks and cautions, not medical advice
As a potent hormone-suppressing drug it must be used under medical supervision. Effects and side effects include altered blood sugar (both highs and lows), suppressed digestion, gallstones with long-term analog use, nausea, and cramping. It is not something to self-administer; the practical medicines are its analogs given in defined clinical situations.
Subjective profileweighing the evidence above
An important regulatory hormone and the basis for real drugs like octreotide, but this is clinical medicine, not a supplement to dabble with.
Resources
This entry is here for reference.
Research
- 1995first citedSomatostatin.
- 2014most active year3 papers
- 2022most recentExploration of Somatostatin Binding Mechanism to Somatostatin Receptor Subtype 4.
- 1.A Pituitary Society update to acromegaly management guidelines
- 2.Pancreatic neuroendocrine tumors: clinical features, diagnosis and medical treatment advances
- 3.Physiology of somatostatin receptors
- 4.Somatostatin.
- 5.Pituitary somatostatin receptor signaling.
- 6.Somatostatin system: molecular mechanisms regulating anterior pituitary hormones.
- 7.Constitutive somatostatin receptor subtype-3 signaling suppresses growth hormone synthesis.
- 8.Somatostatin receptor subtype 2 knockout mice are refractory to growth hormone-negative feedback on arcuate neurons.
- 9.Somatostatin receptors in pituitary and development of somatostatin receptor subtype-selective analogs.
- 10.Somatostatin receptor ligands and resistance to treatment in pituitary adenomas.
- 11.Somatostatin and dopamine receptor regulation of pituitary somatotroph adenomas.
- 12.Acromegaly pathogenesis and treatment.
14 listed here; entry last updated August 2026
Reviews
My notesprivate to this device
FAQ
Is somatostatin a supplement?
No, it's a natural hormone used as a clinical drug, mainly via longer-acting analogs like octreotide.
Why is its half-life so short?
Native somatostatin is rapidly broken down in the blood within a few minutes, which is why analogs were developed.
What is it used for?
Conditions like acromegaly, some neuroendocrine tumors, and acute variceal bleeding, among others.
Can it be taken orally?
No, it's a peptide that would be digested; it's given by infusion or, for analogs, by injection.
Limitations of the evidence
- very short natural half-life, so the hormone itself is impractical as a lasting treatment
Adverse effects
- can raise or lower blood sugar by suppressing both insulin and glucagon
- gastrointestinal effects such as nausea, cramping, or loose stools
- gallstones with long-term analog use, from reduced gallbladder emptying