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Endocrine · Reference monograph

Long-acting (depot) GnRH agonist

Reference compound — not available from Purity Peptides. Shown for research context.

Overview

Leuprorelin, also known as leuprolide, is a synthetic nonapeptide analogue of gonadotropin-releasing hormone (GnRH). Compared with the native decapeptide, it carries a D-leucine at position 6 and a C-terminal proline ethylamide, changes that slow enzymatic breakdown and raise receptor affinity. It belongs to the first generation of GnRH superagonists that emerged in the 1970s and 1980s, after the structure of the native hypothalamic hormone was solved.

Leuprorelin is approved as a prescription medicine in the US and EU for indications that include advanced prostate cancer, endometriosis and central precocious puberty. In the laboratory it is a reference tool for studying the paradox at the centre of GnRH pharmacology: sustained receptor stimulation ultimately silences the pituitary-gonadal axis rather than driving it. Its long-acting microsphere formulations, built on biodegradable polymers, are also frequently cited in pharmaceutical science as an early model of sustained peptide release. Research use centres on receptor desensitisation, sex-steroid suppression models and hormone-dependent tumour biology.

Mechanism studied

  1. Leuprorelin
  2. GnRH receptor
  3. Initial flare → desensitisation
  4. Sex steroids ↓

Leuprorelin binds the GnRH receptor, a Gq-coupled GPCR on pituitary gonadotrophs. Initial exposure stimulates luteinising hormone (LH) and follicle-stimulating hormone (FSH) release, producing the well-described transient flare in gonadal steroids. Because the native hormone normally arrives in pulses, continuous receptor occupancy is unphysiological: over time it leads to receptor uncoupling, internalisation and reduced transcription of gonadotropin subunits. The net result in experimental and clinical studies is sustained suppression of LH, FSH and downstream testosterone or oestradiol, a state often described as reversible medical castration. Direct actions on GnRH receptors expressed in some tumour tissues have also been investigated.

Research highlights

  • 01Developed from structure-activity work on GnRH following its isolation and sequencing in the early 1970s, work linked to the 1977 Nobel Prize in Physiology or Medicine.
  • 02Widely used in rodent and primate models to produce reversible sex-steroid deprivation for endocrine and oncology research.
  • 03Its biodegradable microsphere formulations became a landmark case study in sustained-release peptide engineering.
  • 04Comparative studies against GnRH antagonists have examined the initial flare and its relevance in hormone-dependent tumour models.
  • 05Open questions include the long-term metabolic and cardiovascular effects of androgen deprivation and the role of extra-pituitary GnRH receptors.

Latest published research

3,084 papers on PubMed →

  1. Myomatous erythrocytosis syndrome associated with an 8-kg uterine leiomyoma: a case report of diagnostic evaluation and perioperative management

    Ida N et al. · Case reports in women's health · 2026 Dec · PMID 42774674

  2. Effects of the GnRH agonist leuprorelin on liver volume in premenopausal women with severe polycystic liver disease

    Wijbenga IG et al. · Hepatology communications · 2026 Nov 1 · PMID 42900154

  3. Prostatic Adenosquamous Carcinoma With a Minute Squamous Component in the Initial Biopsy and Early Liver Metastasis: A Case Report

    Tsubouchi Y et al. · IJU case reports · 2026 Nov · PMID 42835373

  4. Interstitial lung disease associated with antiandrogen agents: a pharmacovigilance study based on FDA adverse event reporting system

    Li G et al. · International urology and nephrology · 2026 Nov · PMID 42154420

  5. A Systematic Review of Elagolix for the Management of Endometriosis-associated Pain

    Aafreen S et al. · Annals of African medicine · 2026 Oct 28 · PMID 42937421

  6. Comparison of cardiovascular events in patients with metastatic hormone sensitive prostate cancer treated with LHRH agonists to LHRH antagonists in the US: A retrospective cohort study

    Titus RS et al. · Urologic oncology · 2026 Oct 18 · PMID 42892580

  7. Gonadotropin-releasing hormone antagonists versus agonists for endometriosis: a systematic review and meta-analysis of randomized controlled trials

    Liu T et al. · Frontiers in endocrinology · 2026 · PMID 42953143

  8. Durable biochemical and radiographic response during toripalimab treatment in MSI-high/TMB-high mCRPC: a case report

    Ding J et al. · Frontiers in oncology · 2026 · PMID 42920467

Live feed from PubMed (NCBI) for “Leuprorelin”, updated 2026-10-30. Listing a paper is not an endorsement of its findings.

Registered studies

520 on ClinicalTrials.gov →

From the public ClinicalTrials.gov registry for “Leuprorelin”, updated 2026-10-30. Shown for research context only; Purity Peptides products are not for human use.

Key references

  1. [1]Manufacturer's prescribing information — FDA / EMA / ANVISA
  2. [2]WADA — Prohibited List of Substances and Methods
  3. [3]PubMed — reviews on GnRH agonists in oncology

FAQ

  • Yes. Leuprorelin is the international nonproprietary name and leuprolide is the name used in the United States. Both refer to the same synthetic nonapeptide GnRH agonist, which is also known by several brand names.

  • The pituitary is tuned to pulsatile GnRH signals. Continuous receptor activation by a stable agonist causes desensitisation and receptor downregulation, so after an initial flare, LH and FSH output falls and gonadal steroid production declines.

  • It is classified as a GnRH receptor agonist, a synthetic peptide analogue of a hypothalamic hormone. It is an approved prescription medicine for specific indications, and in research settings it serves as a standard tool for pituitary desensitisation studies.

FOR RESEARCH USE ONLY.Not for human or veterinary use. Not intended to diagnose, treat, cure, or prevent any disease.

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