Compound monograph

Gonadorelin (GnRH-I)

Gonadorelin is the ten-residue hypothalamic releasing hormone GnRH-I, carrying an N-terminal pyroglutamate and a C-terminal amide.

Published: 2026-09-19Last updated: 2026-10-15Literature/identifier verification: 2026-09-17

Also known asGnRH-IGonadotropin-releasing hormoneLHRHLH-RH

Neuropeptides and derived fragments

Identity & nomenclature

Gonadorelin is the ten-residue hypothalamic releasing hormone GnRH-I, carrying an N-terminal pyroglutamate and a C-terminal amide.

GnRH-I is not GnRH-II and not any of the long-acting synthetic GnRH analogs; a generic 'GnRH' label does not identify this decapeptide. Kisspeptin does not become GnRH by cleavage — they are different sequences acting at different receptors, connected by a neuronal circuit.

Canonical name: Gonadorelin.

Declared aliases and development codes: GnRH-I, Gonadotropin-releasing hormone, LHRH, LH-RH.

Molecular properties

Molecular formula	C55H75N17O13
Molecular mass	1182.3 Da
CAS Registry Number	33515-09-2
PubChem CID	638793
UNII	9O7312W37G
Three-letter sequence	pGlu–His–Trp–Ser–Tyr–Gly–Leu–Arg–Pro–Gly
Terminal groups	N-terminal pyroglutamate; C-terminal amide

Ten residues. NO one-letter string is published here because position 1 is pyroglutamate, not glutamine or glutamate, and any standard letter would name a different residue. The C-terminal glycine is amidated. The pyroglutamate ring is internal to that residue; this is NOT a head-to-tail macrocycle.

Structural characteristics

The decapeptide structure was established by conventional sequential analysis of porcine hypothalamic material. Human GnRH-I has the same sequence; the founding determination was not a human isolation. Separate electrophysiology used human kisspeptin-10 to depolarize GnRH neurons in mouse brain slices, with a larger responsive fraction in adults than in juvenile animals. This supplies circuit context for gonadorelin, not evidence that gonadorelin binds KISS1R or that kisspeptin binds the GnRH receptor.

Pyroglutamate at position 1

Terminal features: N-terminal pyroglutamate, C-terminal amide.

Molecular targets & mechanisms

Analytical considerations

Verify pyroglutamate at position 1 and the C-terminal amide specifically, not merely a mass-compatible decapeptide. A single-position substitution, or a D-amino acid in place of its L counterpart, can leave the elemental composition unchanged, so an intact-mass match does not exclude either. A gonadotropin-release response is a functional assay and does not distinguish native GnRH from an active analog.

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.

Often mixed up · Name or substance
GnRH-I vs GnRH-II and synthetic analogs
Often mixed up · Name or substance
GnRH is not cleaved from kisspeptin

What the studies reported

No verified findings are published for this record under Content Policy v1.

Verified bibliography

Cited studies by type

The 2 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.

Reference 1
Structure of the porcine LH- and FSH-releasing hormone. II. Confirmation of the proposed structure by conventional sequential analyses.
Baba Y, Matsuo H, Schally AV
Biochemical and biophysical research communications · 1971-07-16 · Journal Article
current
PMID 4946067 DOI 10.1016/0006-291x(71)90623-1 Gonadorelin (GnRH-I)
Reference 2
Activation of gonadotropin-releasing hormone neurons by kisspeptin as a neuroendocrine switch for the onset of puberty.
Han SK, Gottsch ML, Lee KJ, Popa SM, Smith JT, Jakawich SK, Clifton DK, Steiner RA, Herbison AE
The Journal of neuroscience : the official journal of the Society for Neuroscience · 2005-12-07 · Journal Article
current
PMID 16339030 PMC6725899 DOI 10.1523/jneurosci.3328-05.2005 Gonadorelin (GnRH-I)Kisspeptin-10

Study models of these references

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

Reference	Study models
Baba Y et al. 1971	No abstract available; study type not determined
Han SK et al. 2005	Study models reported: in vitro; animal (mouse) · from the full text

Record history

Published 2026-09-19.

2026-10-15: Sequence and structure

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. Gonadorelin (GnRH-I). Published 2026-09-19; updated 2026-10-15. https://purelypeptides.org/research/compounds/gonadorelin/

Methodology & citation verification

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