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.
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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.
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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–NH2 |
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.
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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.
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Molecular targets & mechanisms
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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.
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Verified bibliography
- Structure of the porcine LH- and FSH-releasing hormone. II. Confirmation of the proposed structure by conventional sequential analyses.current
Baba Y, Matsuo H, Schally AV
Biochemical and biophysical research communications · 1971-07-16 · Journal Article
- Activation of gonadotropin-releasing hormone neurons by kisspeptin as a neuroendocrine switch for the onset of puberty.current
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
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Methodology & citation verification
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