Gonadorelin

Overview

Gonadorelin is the synthetic form of gonadotropin-releasing hormone (GnRH, also called LHRH) — the hypothalamic hormone that sets the entire reproductive axis in motion. It is a decapeptide, ten amino acids long.

GnRH sits one step below kisspeptin in the same chain: where kisspeptin activates the GnRH neurons, gonadorelin acts directly on the pituitary, which then releases the gonadotropins LH and FSH. An essential detail is the rhythm: given pulsatile, GnRH stimulates the axis, but given continuously it actually shuts the axis down (desensitization) — the principle behind GnRH-agonist therapies.

Gonadorelin is an established, approved medicine (diagnostic and therapeutic). That regulatory status is a fact about the respective authorities. At Peptalis, gonadorelin is available strictly for research use only — in-vitro, not for human or animal use.

Mechanism of action

Gonadorelin activates the GnRH receptor on pituitary gonadotrophs; pulsatile it stimulates LH/FSH release, continuous it desensitizes the receptor.

Driving the gonadotropins

• Gonadorelin binds the GnRH receptor on the gonadotroph cells of the pituitary and prompts them to release LH and FSH.
• The rhythm sets the direction: pulsatile release keeps the axis active; continuous exposure desensitizes the receptor and suppresses the axis (Plant 2022).

Diagnostic and physiological use

• The GnRH-stimulation test uses gonadorelin to measure the pituitary response, including in the diagnosis of precocious puberty (Lee 2018; Ahn 2023).
• The response differs by context and genotype, which makes gonadorelin a useful physiological probe (Sansone 2021).

Research findings

• Mechanism/physiology: sustained gonadotropin secretion requires pulsatile GnRH stimulation (Plant 2022)
• Human (clinical): GnRH-stimulation test in men, response by FSHB genotype (Sansone 2021)
• Human (clinical): LH response after gonadorelin stimulation in girls with central precocious puberty (Lee 2018)
• Human (clinical): gonadorelin-stimulation test as a diagnostic reference in precocious puberty (Ahn 2023)

Mechanism

• The GnRH control of the pituitary gonadotropins is extensively worked out; pulsatility determines stimulation versus suppression (Plant 2022).

Human studies

• The gonadorelin (GnRH) stimulation test is used clinically to measure the pituitary response; the response depends among other things on the FSHB genotype (Sansone 2021).
• In girls with central precocious puberty, the LH response after gonadorelin is a diagnostic tool (Lee 2018).
• The intravenous gonadorelin test serves as a reference in the diagnosis of central precocious puberty (Ahn 2023).

Research context

This profile describes what has been done and found in research. Regulatory and clinical facts are facts about the respective trials and authorities, not claims about a Peptalis product; the compound is for in-vitro laboratory research only (RUO).

Open questions

• Gonadorelin is short-acting; its behaviour depends strongly on the delivery rhythm (pulsatile versus continuous).
• The data reported in studies mainly concern diagnostic/physiological use; they are recorded as facts about the studies, not as a recommendation.
• The relationship with the upstream kisspeptin step remains an active area of research.

Research outlook

Gonadorelin is the well-characterized, clinically validated anchor of the GnRH step in the reproductive axis.

Together with kisspeptin-10 it makes the neuroendocrine control of reproduction within the domain internally comparable (top-down: kisspeptin → GnRH → LH/FSH).

Scientific interest

The established, approved anchor of the GnRH step — a comparison neighbour of kisspeptin-10.

An instructive rhythm principle: pulsatile stimulates, continuous suppresses.

Extensive clinical and physiological literature.

Specifications

References

1. The effect of overweight on the luteinizing hormone level after gonadorelin stimulation test in girls with idiopathic central precocious puberty · Lee HY, et al. · Ann Pediatr Endocrinol Metab · 2018
2. Pituitary response to GnRH stimulation tests in different FSHB-211 G/T genotypes · Sansone A, et al. · Hum Reprod · 2021
3. Recognition that sustained pituitary gonadotropin secretion requires pulsatile GnRH stimulation: a Pittsburgh Saga · Plant TM · F S Rep · 2022
4. Use of the Subcutaneous Triptorelin Stimulation Test for Diagnosis of Central Precocious Puberty · Ahn J, et al. · Children (Basel) · 2023

Availability

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