Gonadorelin peptide: handling, salt forms and GnRH pulsing

Gonadorelin is synthetic gonadotropin-releasing hormone (GnRH): ten amino acids, the same sequence the hypothalamus makes, with no modifications. We sell it in a 5 mg vial.

Identity

Both ends of the chain are capped. The first residue is pyroglutamate (pGlu), a ring that closes the N-terminus, and the last is an amide. Those two caps are part of the natural hormone, not additions.

Salt forms change the numbers

Gonadorelin is commonly supplied as a salt, most often the acetate. The salt adds weight without adding peptide, so a milligram of gonadorelin acetate holds slightly fewer peptide molecules than a milligram of the free peptide. If your protocol runs in molar units, take the form from the batch's lab report and use the matching molecular weight. The QR code on every pepuro vial opens that report.

Why pulsing matters in GnRH research

The hypothalamus releases GnRH in pulses, not as a steady stream, and the receptor it acts on in the pituitary responds to that pattern. In research models, pulsed exposure to GnRH stimulates release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Continuous exposure does the opposite: the receptor desensitizes and the response falls away.

That split is the central fact of GnRH research, and it is why the long-acting GnRH analogs exist. Leuprolide and triptorelin put a D-amino acid at position 6, and leuprolide also shortens the C-terminus to an ethylamide. Those changes make them bind more tightly and break down more slowly, so they act continuously. Gonadorelin, the unmodified sequence, is cleared within minutes, so it is the form used when the pattern of exposure is what is being studied.

Concentration

As the free peptide, a 5 mg vial holds about 4.23 micromoles. At 1, 2, 3 and 5 mL of water that is roughly 4.23, 2.11, 1.41 and 0.85 mM. For a salt form, recalculate with the weight on the report. The gonadorelin calculator takes any water volume.

Handling

Gonadorelin ships as a lyophilized powder. Add bacteriostatic water down the inside of the glass, swirl gently and never shake. Keep dry vials in the freezer long term or the fridge short term. Once reconstituted, keep the vial in the fridge and split it into aliquots rather than refreezing it. The reconstitution guide has the full method.

Reading a gonadorelin lab report

A gonadorelin report should show:

• an observed mass near 1182.29 for the peptide itself
• the salt form, if it is supplied as one
• purity at 99% or higher by HPLC
• a batch number that matches the vial, and a named lab

How to read a peptide lab report explains each line.

Upstream and downstream

Gonadorelin sits in the middle of a signalling chain. Kisspeptin-10 acts upstream, on the neurons that release GnRH. HCG acts downstream, on the LH receptor that GnRH-driven LH would normally reach. Research on the reproductive axis often uses more than one of the three.

Every gonadorelin vial from pepuro ships free, from our Calgary, Toronto and Vancouver distribution centers, the same business day your e-Transfer clears, with a QR code on the vial that opens its independent, third-party lab report.

For research use only. Not for human or animal consumption.