Gonadorelin

Gonadorelin is synthetic gonadotropin-releasing hormone, a hypothalamic peptide that stimulates pituitary gonadotropin release. Its principal veterinary applications are reproductive management in cattle, including treatment of follicular ovarian cysts and control of ovulation within synchronization programs. It also has selected specialist diagnostic and reproductive applications in other species.

Group

GnRH analogue

Mechanism of Action

Gonadorelin activates GnRH receptors on anterior pituitary gonadotrophs, triggering release of luteinizing hormone and, to a lesser degree, follicle-stimulating hormone. In a responsive ovary, the resulting LH signal can induce ovulation or luteinization of a follicle. Incorporating this response into reproductive protocols helps coordinate follicular development and ovulation with breeding.

Dose Rates

Dog

Use / stage	Dose	Route	Schedule	Instructions
Ovulation induction	Reference only	IM		Source: 50–100 mcg/dog “per day” every 24–48 hours. Salt basis and schedule wording require clarification.
Cryptorchidism stimulation test	50 mcg	IM	Once	Collect baseline testosterone and repeat sampling 2–3 hours after injection.
Cryptorchidism stimulation test	2.5 mcg/kg	IM	Once	Collect baseline and 60–90 minute testosterone samples. A 25 mcg fixed alternative is described for very small dogs without a weight cutoff; do not automatically substitute it.
Cystic ovarian disease	3.3 mcg/kg	IM	Every 24 h	Up to 3 days; Assess progesterone after 1–2 weeks; a value above 2 ng/mL supports response.
Reduced libido	50–100 mcg	IM	Every 168 h	Up to 42 days; Anecdotal weekly course lasting 4–6 weeks.

Cat

Use / stage	Dose	Route	Schedule	Instructions
Ovulation induction	Reference only	IM		25 mcg per cat once; source does not specify salt/base basis.

Cattle

Use / stage	Dose	Route	Schedule	Instructions
Follicular ovarian cysts	100 mcg	IM	Once	Gonadorelin amount, supplied as hydrochloride in the 50 mcg/mL Factrel formulation; equivalent to 2 mL. Follicular ovarian cysts in cows and replacement heifers.
Follicular ovarian cysts	Reference only	IV		100 mcg per cow once is stated for diacetate tetrahydrate; hydrochloride is separately stated for IM use. Salt-labelled and gonadorelin-equivalent strengths are not interchangeable.
Reproductive synchronization	Reference only	IM		Factrel-based timed-insemination framework: gonadorelin 100–200 mcg IM on day 0; dinoprost 25 mg IM 6–8 days later; a second gonadorelin 100–200 mcg IM dose 30–72 hours after dinoprost; timed insemination 0–24 hours after that dose, or breeding on observed estrus. Combined calendar protocol, not a single-dose calculator regimen.

Ferret

Use / stage	Dose	Route	Schedule	Instructions
Persistent estrus	20 mcg	IM		Most effective about 14 days after estrus onset; repeat in one week if necessary.

Indications

Treatment of follicular ovarian cysts in cattle by inducing ovulation or luteinization of responsive follicular tissue.
Synchronization of ovulation in cattle as part of timed artificial-insemination or other controlled breeding protocols.
Induction of ovulation in selected animals with a mature responsive follicle within a species-specific reproductive plan.
Specialist diagnostic stimulation of gonadotropin or gonadal hormone responses during investigation of selected reproductive disorders.

Contraindications

Pregnancy unless a specifically justified reproductive protocol applies.

Interactions

No specific animal interactions reported.

Adverse effects

Excessive endocrine effects are possible; specific adverse reactions are not described.

Preparations

Preparation	Form	Strength	Route
Gonadorelin diacetate tetrahydrate 50 mcg/mL Source explicitly states equivalent to 43 mcg/mL gonadorelin.	Injection	50 mcg / mL	IM, IV
Gonadorelin as hydrochloride 50 mcg/mL Strength expressed as gonadorelin, not hydrochloride salt mass.	Injection	50 mcg / mL	IM

Monitoring and Administration

Monitor ovulation and reproductive response. Prevent handler exposure, especially during pregnancy.

Hydrochloride and diacetate-tetrahydrate labelled strengths must be distinguished; the source equates 50 mcg diacetate tetrahydrate with 43 mcg gonadorelin.