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Catalog/Gonadorelin

Gonadorelin

Also known as GnRH · LHRH · Gonadoliberin · Luteinizing hormone-releasing hormone · Factrel · Lutrepulse

Synthetic GnRH — the native decapeptide at the top of the pituitary-gonadal axis; pulsatile dosing switches the axis on, continuous dosing shuts it down.

Research refreshed

Overview

Gonadorelin is synthetic gonadotropin-releasing hormone (GnRH), the ten-amino-acid hypothalamic hormone that governs reproduction. Delivered to the pituitary it triggers release of LH and FSH — but only when given in pulses: the receptor’s defining quirk is that continuous exposure desensitizes it and suppresses the very hormones a pulse would release, the paradox that underlies both fertility and hormone-suppression medicine.

Background

Gonadorelin is the manufactured form of GnRH, the master hormone of reproduction. Isolated and sequenced in 1971 — work that earned Andrew Schally a share of the 1977 Nobel Prize — it sits one step below kisspeptin in the hypothalamic-pituitary-gonadal (HPG) axis and one step above LH and FSH. Its ten residues are the switch that turns the whole reproductive cascade on.

What makes GnRH biology remarkable is its dependence on rhythm. The pituitary responds to pulses, not to a steady signal: given in a pulsatile pattern gonadorelin stimulates LH and FSH and can reawaken a dormant axis, but given continuously it does the opposite — the receptor downregulates and gonadotropins fall. That single paradox splits its uses in two. Pulsatile gonadorelin was FDA-approved (Lutrepulse, via a programmable pump) for infertility from hypothalamic amenorrhea, and a version (Factrel) served as a diagnostic of pituitary function; both were later discontinued in the US. The same continuous-suppression principle is why long-acting GnRH analogs such as leuprolide are used to shut the axis down.

In practice gonadorelin draws attention as the axis-signaling counterpart to hormones this catalog already covers: it acts upstream of hCG — which mimics LH at the gonad — and downstream of kisspeptin, which triggers GnRH release in the first place. Its native half-life, measured in minutes, is precisely why the pulsatile-versus-continuous distinction matters so much.

Mechanism

GnRH-receptor agonism on pituitary gonadotrophs. Pulsatile stimulation drives LH / FSH secretion; continuous stimulation desensitizes the receptor and suppresses the gonadotropins.

Key research findings

  • Native GnRH decapeptide — the manufactured form of the hypothalamic hormone that controls LH and FSH; sequenced in 1971 (Schally, Nobel 1977).
  • Pulsatile vs continuous — the defining paradox: pulses stimulate the gonadotropins, continuous exposure desensitizes the receptor and suppresses them.
  • Approved uses (historical) — pulsatile Lutrepulse for hypothalamic-amenorrhea infertility and Factrel as a pituitary-function diagnostic; both discontinued in the US.
  • Axis position — acts downstream of kisspeptin (which releases GnRH) and upstream of hCG (which mimics LH at the gonad).
  • Short half-life — a native peptide cleared within minutes, which is why delivery pattern, not just dose, determines the effect.

How Gonadorelin is made

Behind every vial of Gonadorelin is the same exacting pipeline every research peptide runs — but the chemistry plays out differently for this molecule. Here is how Gonadorelin, specifically, is brought into being.

  1. On paper first

    On paper, Gonadorelin is C55H75N17O13 — about 1,182.29 daltons of precisely arranged atoms. Before a single bond is made, the target sequence, salt form, and purity threshold are written down as the contract the finished material must meet.

  2. Built residue by residue

    Gonadorelin is built one protected residue at a time by solid-phase synthesis, each cycle a deprotection, a coupling, and a wash. Its C-terminus is amidated rather than left as a free acid — a defined modification the synthesis has to deliver, not an afterthought.

  3. Purity is won here

    The crude mixture — Gonadorelin plus its deletions and side products — is then separated on preparative HPLC, and where the cut is taken decides the difference between a genuinely pure peptide and a barely-passable one.

  4. Proven, then protected

    A real batch of Gonadorelin proves itself: identity confirmed by mass spectrometry against its ~1,182.29 Da, purity read directly off an analytical HPLC trace, water and counterion content measured. That batch-specific certificate of analysis is the only honest way to know what is actually in a vial of Gonadorelin — and a short, cold, accountable chain of custody is how that purity survives the trip to your bench.

Walk the full synthesis pipeline

Handling, storage & why purity is hard

Gonadorelin is the native GnRH decapeptide: an N-terminal pyroglutamate, a C-terminal glycinamide, and otherwise standard residues. Solid-phase assembly is routine, but the pyroglutamate terminus and the C-terminal amide are the two features that must be formed correctly, and the internal Ser/Tyr residues make byproduct control the main purity task.

Moderate synthesisC-terminal amide

Don't judge a vial by its cake. A fluffy, good-looking lyophilized powder reflects bulking agents and freeze-drying parameters — not purity. Insist on a batch-specific certificate of analysis.

How peptides are made — the full pipeline

Research areas

  • Reproductive endocrinology
  • HPG-axis function
  • Fertility
  • Hypogonadism

Research-area guides

Latest research

Recent clinical trials and publications mentioning Gonadorelin, pulled automatically from ClinicalTrials.gov and PubMed and refreshed daily. Listings are unfiltered search results, not curated endorsements.

Frequently asked questions

What is gonadorelin?+

Gonadorelin is synthetic GnRH — the natural ten-amino-acid hypothalamic hormone that tells the pituitary to release LH and FSH, the hormones that drive the gonads.

Why does pulsatile versus continuous dosing matter?+

The GnRH receptor responds to rhythm: pulses stimulate LH and FSH, while continuous exposure desensitizes the receptor and suppresses them — the basis for both fertility and hormone-suppression uses.

How does gonadorelin relate to hCG and kisspeptin?+

It sits between them on the reproductive axis: kisspeptin triggers GnRH (gonadorelin) release, gonadorelin drives LH and FSH, and hCG acts further down by mimicking LH directly at the gonad.

Is gonadorelin FDA-approved?+

It was historically approved in the US (Lutrepulse for infertility; Factrel as a diagnostic) but both were discontinued. This page is a research and educational reference, not medical advice.

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