Kisspeptin-10 vs. hCG. vs. Gonadorelin

[AASraw]

Kisspeptin-10 is well-known for its ability to promote the release of gonadotropin. In addition to Kisspeptin-10, other common substances that can participate in the release of gonadotropin include Human Chorionic Gonadotropin (hCG) and Gonadorelin (GnRH).​

hCG: hCG is a hormone produced during pregnancy by the placenta. It binds to the LH receptor (LHR) on gonadal cells, primarily in the ovaries and testes. This leads to stimulation of gonadal hormone production (such as testosterone in men and progesterone/estrogen in women) and induces ovulation in women (through its LH-like effect).

Gonadorelin: Gonadorelin is a synthetic version of GnRH, a hormone released by the hypothalamus that stimulates the pituitary gland to release LH and FSH. Unlike kisspeptin, which activates GnRH neurons, gonadorelin directly activates the GnRH receptor (GnRHR) on the pituitary, which then triggers the release of LH and FSH.

Here is a table that summarize their difference:

Aspect	Kisspeptin-10	hCG	Gonadorelin
Mechanism	Activates KISS1R on GnRH neurons to stimulate pulsatile GnRH release	Binds LH receptor on gonads to stimulate gonadal hormones	Activates GnRH receptor on pituitary to release LH/FSH
Primary Use	Ovulation induction, male hypogonadism, controlled ovarian hyperstimulation (COH), IVF	Ovulation induction, male hypogonadism, controlled ovarian hyperstimulation (COH), IVF	Treatment of hypogonadotropic hypogonadism, fertility, controlled ovarian hyperstimulation (COH), diagnostic use
Half-life	Short (minutes to hours)	Long (24-36 hours)	Very short (minutes)
Side effects	Few side effects, generally well-tolerated	Ovarian hyperstimulation syndrome (OHSS), multiple pregnancies	Potential receptor desensitization with continuous use
Advantages	Mimics natural, pulsatile GnRH release, fewer side effects than hCG	Strong LH-like activity, effective for ovulation induction	Physiological control of LH/FSH release, mimics natural GnRH pulse