Gonadorelin
Gonadorelin is the decapeptide identical to natural GnRH. It was approved and marketed as a diagnostic agent (for example, Factrel) to assess pituitary gonadotropin reserve, and, delivered in a pulsatile fashion (for example, Lutrepulse), to induce ovulation in women with hypothalamic amenorrhea. Many branded gonadorelin products have since been discontinued in some markets, and it is now frequently supplied through pharmacy compounding; approval status differs across regions.
Mechanism
In plain terms, gonadorelin is a copy of the brain hormone that tells the pituitary to release the hormones controlling the ovaries and testes. Technically, it is a decapeptide agonist of the GnRH receptor on pituitary gonadotrophs; when delivered in physiological pulses it stimulates secretion of luteinising hormone (LH) and follicle-stimulating hormone (FSH), whereas continuous (non-pulsatile) exposure paradoxically desensitises the receptor and suppresses gonadotropins, the principle exploited by long-acting GnRH analogues.
Regulatory Status by Region
- United States (FDA)Has a history of FDA approval: gonadorelin hydrochloride (Factrel) for evaluating pituitary gonadotropic function and gonadorelin acetate (Lutrepulse) for pulsatile induction of ovulation in hypothalamic amenorrhea. Several branded products have since been discontinued in the US (not for safety reasons), and gonadorelin is now commonly supplied via pharmacy compounding.
- Australia (TGA)Gonadorelin (native GnRH) has been used clinically in Australia for diagnostic and fertility indications; its current ARTG registration should be verified. Related GnRH analogues (e.g., leuprorelin, goserelin) are registered.
- European Union (EMA)Gonadorelin has been marketed in European countries through national approvals (as a diagnostic agent and for pulsatile fertility therapy) rather than through a single centralised EMA authorisation.
- WADAProhibited in males under Section S2: WADA lists gonadotropin-releasing hormone (GnRH) agonists among luteinising-hormone releasing factors, and gonadorelin is explicitly named; it is not prohibited in females.
Key Studies
- Structure of the porcine LH- and FSH-releasing hormone (the amino acid sequence of GnRH/LHRH) (Matsuo H, Baba Y, Nair RM, Arimura A, Schally AV. Biochem Biophys Res Commun. 1971.)
- Pregnancies following chronic intermittent (pulsatile) administration of Gn-RH in hypothalamic amenorrhea (Leyendecker G, Wildt L, Hansmann M. J Clin Endocrinol Metab. 1980.)