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Compound monograph

Glucagon

Glucagon is the endogenous 29-residue pancreatic hormone and the native ligand of the glucagon receptor. Horváth et al. (PMID 37528104) place glucagon among the gastrointestinal peptides of the glucagon family.

Published: 2026-09-14Last updated: 2026-10-14Literature/identifier verification: 2026-09-14
Also known asGlucagon(1-29)
Incretin and glucagon receptor ligands

01

Identity & nomenclature

Glucagon is the endogenous 29-residue pancreatic hormone and the native ligand of the glucagon receptor. Horváth et al. (PMID 37528104) place glucagon among the gastrointestinal peptides of the glucagon family.

Mature glucagon, not proglucagon and not a generic glucagon-family peptide. PubChem CID 16132283 encodes the free 29-residue peptide, whereas CAS-associated CIDs 91820614 and 16186213 include acetate and hydrochloride components, respectively. Glucagon, GLP-1 and oxyntomodulin are related through processing of a shared precursor but are not aliases. Note particularly that this entire 29-residue sequence is contained within oxyntomodulin, which extends it by eight residues — that containment is exactly why the two are analytically difficult to separate.

Declared aliases and development codes: Glucagon(1-29).

02

Molecular properties

Molecular formulaC153H225N43O49S
Molecular mass3482.8 Da
CAS Registry Number16941-32-5
PubChem CID16132283
UNII76LA80IG2G
One-letter sequenceHSQGTFTSDYSKYLDSRRAQDFVQWLMNT
Terminal groupsFree N-terminus; Free C-terminal carboxyl

Twenty-nine residues, free at both termini, no modifications.

03

Structural characteristics

Cryo-electron microscopy structures of glucagon bound to the human glucagon receptor in complex with two different heterotrimeric G proteins establish exact-hormone receptor recognition, with conformational differences in the receptor intracellular loops identified as selectivity determinants and supported by mutagenesis. Being an agonist at this receptor does not, in the other direction, establish a glucagon-derived backbone: compounds in this library activate the glucagon receptor from scaffolds that are not glucagon-derived at all.

Terminal features: Free N-terminus, Free C-terminal carboxyl.

04

Molecular targets & mechanisms

Glucagon receptor

GCGR

GCGR is a class B G-protein-coupled receptor. Retatrutide's LY3437943 discovery record characterizes a molecular agonist relationship at GCGR alongside GIPR and GLP-1R.

05

Analytical considerations

A shared glucagon-region epitope or internal sequence is insufficient to discriminate glucagon from larger proglucagon-derived peptides that contain it in full. Identity work should target intact-molecule specificity and calibrant identity rather than assuming all glucagon-reactive material is mature glucagon. A validated mass-spectrometric method separating glucagon from oxyntomodulin exists and is the appropriate reference point for that problem. GSRS UNII 76LA80IG2G matches the peptide sequence but reports C153H225N43O48S, one oxygen below PubChem CID 16132283 and this record’s formula.

Disagreements and mix-ups

Points where sources disagree about this compound's identity, or where a name or form is easily confused with another, as noted in this record. The discrepancy register quotes the passage for each one.

What the studies reported

Each finding describes one cited study in its stated model. These observations are specific to that study and do not establish effects in other settings.

Cell and tissue studies

  • Human GCGR-Gs and GCGR-Gi1 receptor complexes

    Qiao et al. reported cryo-electron microscopy structures of human GCGR bound to glucagon with either Gs or Gi1, with both complexes adopting a similar open binding cavity.

    Reference [1]

  • Plasma liquid chromatography-tandem mass spectrometry assay

    Becker et al. validated a liquid chromatography-tandem mass spectrometry assay for glucagon in plasma that was linear from 1.3 to 14.7 pM and had imprecision below 13% CV.

    Reference [2]

  • CHO-K1 cells expressing human GCGR

    Zimmermann et al. measured an EC50 of 20 pM for glucagon in CHO-K1 cells expressing human GCGR.

    Reference [3]

06

Verified bibliography

Cited studies by type

The 4 papers this record cites, counted by the kind of work each reports. A count is the size of this record's selection, not of the research that exists, and says nothing about results, safety, effectiveness or approval.

A paper can report more than one kind of work. Each count opens those papers in the bibliography. Compare every record on the Evidence Map.

  1. Reference 1

    Structural basis of G(s) and G(i) recognition by the human glucagon receptor.

    Qiao A, Han S, Li X, Li Z, Zhao P, Dai A, Chang R, Tai L, Tan Q, Chu X, Ma L, Thorsen TS, Reedtz-Runge S, Yang D, Wang MW, Sexton PM, Wootten D, Sun F, Zhao Q, Wu B

    Science (New York, N.Y.) · 2020-03-20 · Journal Article

    current
    PMID 32193322DOI 10.1126/science.aaz5346GlucagonGCGR

  2. Reference 2

    Quantification of glucagon and oxyntomodulin by protein precipitation-immunoaffinity enrichment-LC-MS/MS.

    Becker JO, Shijo SK, Huynh HH, Forrest KL, MacCoss MJ, Emrick MA, Goonatilleke E, Hoofnagle AN

    Journal of mass spectrometry and advances in the clinical lab · 2025-04-11 · Journal Article

    current
    PMID 40385697PMC12083559DOI 10.1016/j.jmsacl.2025.04.002GlucagonOxyntomodulin

  3. Reference 3

    BI 456906: Discovery and preclinical pharmacology of a novel GCGR/GLP-1R dual agonist with robust anti-obesity efficacy.

    Zimmermann T, Thomas L, Baader-Pagler T, Haebel P, Simon E, Reindl W, Bajrami B, Rist W, Uphues I, Drucker DJ, Klein H, Santhanam R, Hamprecht D, Neubauer H, Augustin R

    Molecular metabolism · 2022-11-07 · Journal Article

    current
    PMID 36356832PMC9679702DOI 10.1016/j.molmet.2022.101633SurvodutideGlucagonGLP-1RGCGR

  4. Reference 4

    Polymorphic amyloid nanostructures of hormone peptides involved in glucose homeostasis display reversible amyloid formation.

    Horváth D, Dürvanger Z, K Menyhárd D, Sulyok-Eiler M, Bencs F, Gyulai G, Horváth P, Taricska N, Perczel A

    Nature communications · 2023-08-01 · Journal Article

    current
    PMID 37528104PMC10394066DOI 10.1038/s41467-023-40294-xGIP(1-42)GlucagonGLP-1(7-36) amideGLP-1(7-37)Human GLP-2(1-33)Exenatide

Study models of these references

What kind of experiment each cited paper reports, taken from its abstract unless marked. Not a summary of results.

ReferenceStudy models
Qiao A et al. 2020Study models reported: in vitro · from the abstract
Becker JO et al. 2025Study models reported: in vitro · from the abstract
Zimmermann T et al. 2022Study models reported: in vitro; animal (mouse, beagle dog) · from the full text
Horváth D et al. 2023Chemical, structural or analytical study; no biological model reported

Compare

Record history

Published 2026-09-14.

  • : Sequence and structure
  • : Identity and nomenclature, Analytical notes
  • : Identity and nomenclature, References

Each entry names the parts of this record that changed on that date. Changes to links between records and to catalogue links are not listed. This history covers the tracked record fields; study findings are not listed here.

Cite this record: Purely Peptides Research Library. Glucagon. Published 2026-09-14; updated 2026-10-14. https://purelypeptides.org/research/compounds/glucagon/

10

Methodology & citation verification

Reference identity is checked against official PubMed metadata. Local deterministic receipts bind each normalized title and canonical metadata record to its verification date. Scientific values remain absent when an authoritative source has not been verified.

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