Overview
Following subcutaneous administration, gonadorelin acetate is absorbed with a Tmax of approximately 20–40 minutes and a subcutaneous half-life of roughly 30–60 minutes (versus ~2–4 minutes IV). It is rapidly metabolized by endopeptidases and tissue-bound proteases, particularly at the Tyr5-Gly6 and Pro9-Gly10 bonds. Binding to GnRH-R on gonadotrophs initiates PKC-mediated phosphorylation cascades that upregulate LHβ and FSHβ subunit gene transcription via AP-1 and SF-1 transcription factors. LH pulses downstream drive Leydig cell StAR protein expression and CYP17A1/CYP11A1-mediated testosterone biosynthesis. FSH acts on Sertoli cells via cAMP/PKA pathways to support androgen-binding protein (ABP) secretion and spermatogenesis. With exogenous androgen use, Leydig cell atrophy and reduced intratesticular testosterone (ITT) occur; gonadorelin counteracts this by maintaining endogenous LH pulses.
Proposed mechanism
Gonadorelin binds to GnRH receptors (GnRH-R) on pituitary gonadotroph cells, activating Gq/11-coupled signaling and triggering phospholipase C-mediated IP3 and DAG production, which raises intracellular calcium and activates protein kinase C. This cascade promotes synthesis and pulsatile secretion of LH and FSH from the anterior pituitary. LH then acts on Leydig cells in the testes to stimulate testosterone synthesis via the cAMP-PKA pathway, while FSH acts on Sertoli cells to maintain spermatogenesis.
What the evidence supports
Randomised controlled trial data in humans exists and supports use in specific contexts.
Graded Clinical
Findings supported by randomised, controlled trials in humans, with pre-registered endpoints and published results.
Key citations
Representative primary sources, including results that did not favour the compound.
- [1]
Pulsatile GnRH therapy to induce fertility in a man with hypogonadotropic hypogonadism
· Fertility and Sterility — general review of GnRH pulsatile therapy literature · 2020
- [2]
Millar RP et al. Gonadotropin-releasing hormone receptors
· Endocrine Reviews, 25(2):235-275. DOI: 10.1210/er.2003-0002 · 2004
- [3]
Spratt DI et al. Pulsatile gonadotropin-releasing hormone administration in normal men — response to physiologic and supraphysiologic doses
· Journal of Clinical Endocrinology & Metabolism, 63(5):1179-1184 · 1986
- [4]
Liu PY et al. The rationale, efficacy and safety of androgen therapy in older men: future research and current practice recommendations
· Journal of Clinical Endocrinology & Metabolism, 89(10):4789-4796 · 2004
Citation records in this build are illustrative placeholders for the design.
Reference information for research purposes. Not medical advice, and not a recommendation to use any compound. Many entries describe substances that are not approved for human use.