PeptideHormone

SomatostatinSST

The brake on the growth-hormone axis — and much else.

EndogenousEstablishedCompare lineage

Identity

Class
Cyclic peptide (14 and 28 aa forms)
Source
Hypothalamus, pancreatic delta cells, GI tract
Receptor
Somatostatin receptors SSTR1–SSTR5

Key properties

Molecular weight
~1,637.9 Da
Half-life (native)
~1–3 min (very short)
Model dosing

Approximate values for the native hormone. Engineered analogs are often deliberately larger and far longer-acting.

Mechanism

Somatostatin inhibits GH (and TSH) release from the pituitary and broadly suppresses endocrine and exocrine secretion across the GI tract and pancreas. It is the inhibitory counterweight that, opposing GHRH, sculpts GH pulses.

Reference notes

  • Any account of GH timing has to include somatostatin — it sets the troughs between pulses.
  • Its broad inhibitory reach extends well beyond GH, into gut and pancreatic secretion.
  • Stable somatostatin analogs are long-established tools in endocrinology.

Selected literature

Curated peer-reviewed reviews, sourced from PubMed. Selected for relevance, not exhaustive — open any entry on PubMed for the full record and its primary citations.

  1. 1.Structure and Function of Somatostatin and Its Receptors in Endocrinology · Endocrine reviews, 2025 · PMID 39116368
  2. 2.Somatostatin · The New England journal of medicine, 1983 · PMID 6139753