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Metabolic & GLP-1 · Reference monograph

Glucagon-like peptide-1, an endogenous incretin

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

Overview

Glucagon-like peptide-1 (GLP-1) is an incretin hormone produced by intestinal L-cells, which are most abundant in the distal ileum and colon, and by a population of neurons in the brainstem nucleus of the solitary tract. It derives from proglucagon through tissue-specific processing by prohormone convertase 1/3. The principal circulating bioactive forms are GLP-1(7-36) amide and GLP-1(7-37).

GLP-1 was predicted after the proglucagon gene was cloned in the early 1980s, and the insulinotropic truncated forms were identified in the mid-1980s through work by Svetlana Mojsov, Joel Habener, Daniel Drucker, Jens Juul Holst and others. Native GLP-1 has a half-life of only minutes because DPP-4 rapidly removes its first two residues, a limitation that drove development of DPP-4 inhibitors and degradation-resistant receptor agonists, now among the most studied drug classes. GLP-1 itself is an endogenous peptide used in research on incretin physiology, beta-cell signalling, the gut-brain satiety axis and peptide degradation. Habener, Mojsov and Lotte Bjerre Knudsen received a 2024 Lasker Award for work in this field.

Mechanism studied

  1. L-cells
  2. GLP-1
  3. Insulin ↑ / glucagon ↓
  4. Satiety

GLP-1 binds the GLP-1 receptor, a class B G protein-coupled receptor expressed on pancreatic beta cells, vagal afferent neurons, specific brain regions, the heart, kidney and gastrointestinal tract. Receptor activation couples mainly to Gs, elevating cAMP and engaging protein kinase A and Epac2. In beta cells this amplifies insulin exocytosis only when glucose is elevated, the defining glucose-dependence of incretin action. GLP-1 also suppresses glucagon secretion, partly via somatostatin from delta cells, slows gastric emptying and reduces food intake through vagal and central pathways. Because DPP-4 cleavage yields GLP-1(9-36) amide, much intestinally released GLP-1 is degraded before reaching the systemic circulation.

Research highlights

  • 01Predicted from the proglucagon gene sequence in the early 1980s; insulinotropic GLP-1(7-37) was characterised in 1986-1987.
  • 02The incretin effect, in which nutrients in the gut elicit a larger insulin response than an equivalent rise in blood glucose alone, is attributed largely to GLP-1 and GIP.
  • 03DPP-4 degradation research led directly to two drug classes: DPP-4 inhibitors and degradation-resistant receptor agonists.
  • 04Brainstem preproglucagon neurons provide a central GLP-1 source distinct from gut-derived hormone.
  • 05Open questions include how peripheral GLP-1 signals reach the brain and which receptor-expressing neurons mediate satiety.

Latest published research

34,295 papers on PubMed →

  1. Future Treatments for Tobacco Dependence

    Jimenez-Ruiz CA et al. · Open respiratory archives · 2027 Mar · PMID 42892933

  2. Mulberry leaf flavonoids alleviate type 2 diabetes by remodeling the gut microbiota-bile acid axis and activating FXR signaling

    Shi L et al. · Journal of ethnopharmacology · 2027 Jan 10 · PMID 42503322

  3. Metformin Use Is Associated With Reduced Rates of Primary Nerve Decompression Surgery and Revision in Type 2 Diabetes: A Retrospective Cohort Study

    Abbas Y et al. · Journal of hand surgery global online · 2027 Jan · PMID 42927270

  4. The gut-pancreas axis in chronic pancreatitis: Microbiota-endogenous GLP-1 interactions and candidate repair pathways

    Fan Z et al. · Microbiological research · 2027 Jan · PMID 42854469

  5. Discovery of Fisetin as a potent and cell-active ACVR2A inhibitor

    Bu X et al. · Bioorganic & medicinal chemistry letters · 2027 Jan · PMID 42801961

  6. Immunometabolic regulation of macrophage function in cardio-hepatic-renal comorbidities: Mechanisms and therapeutic opportunities

    Bai X et al. · Molecular and cellular endocrinology · 2027 Jan · PMID 42759644

  7. Metabolic effects of a GLP-1 analog combined with aerobic training in ovariectomized rats

    Selau B et al. · Molecular and cellular endocrinology · 2027 Jan · PMID 42727623

  8. Oxidative stress, aging, metabolism, SIRT1, and the gut microbiota: the neurocardiac basis of cognitive loss

    Maiese K et al. · Medical gas research · 2027 Jan 1 · PMID 42545731

Live feed from PubMed (NCBI) for “GLP-1 (Glucagon-like Peptide-1)”, updated 2026-10-30. Listing a paper is not an endorsement of its findings.

Registered studies

2,172 on ClinicalTrials.gov →

From the public ClinicalTrials.gov registry for “GLP-1 (Glucagon-like Peptide-1)”, updated 2026-10-30. Shown for research context only; Purity Peptides products are not for human use.

Key references

  1. [1]Drucker, 2018 — Cell Metab
  2. [2]PubMed — reviews on GLP-1 and incretin physiology

FAQ

  • The incretin effect describes the observation that glucose taken in with food stimulates considerably more insulin secretion than the same glycaemic rise produced without gut involvement. GLP-1 and GIP, released from the intestine, account for most of this amplification in healthy physiology.

  • The enzyme dipeptidyl peptidase-4 cleaves the first two amino acids of GLP-1 within minutes, producing a metabolite with little insulinotropic activity. The peptide is also cleared rapidly by the kidneys. Engineered agonists use amino acid substitutions, fatty acid acylation or protein fusion to overcome these limitations.

  • The receptor is found on pancreatic beta cells, some delta cells, vagal sensory neurons, discrete brain nuclei including the hypothalamus and area postrema, and in tissues such as the heart, kidney, stomach and intestine. Mapping receptor expression precisely remains technically challenging because of antibody specificity issues.

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

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