Ganirelix

Gonadotropin-releasing hormone (GnRH) is a hypothalamus-derived releasing hormone responsible for the synthesis and release of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) from the anterior pituitary. At midcycle, a large increase in GnRH release results in an LH surge, which leads to several physiologic actions such as ovulation, resumption of meiosis in the oocyte, and luteinization. Luteinization results in a rise in serum progesterone with an accompanying decrease in estradiol levels.

Controlled ovarian hyperstimulation (COH) is performed in conjunction with other interventions like in vitro fertilization (IVF) during assisted reproductive technology (ART). COH is beneficial as it allows the scheduling of IVF treatments. During this intervention, inhibiting premature surges of LH is important because premature elevated LH levels can hinder effective multiple follicular maturation and can lead to an undesirable increase in progesterone levels. Ganirelix aims to suppress premature LH surges by competitively blocking the GnRH receptors on the pituitary gonadotroph and subsequent transduction pathways. Ganirelix-induced suppression of gonadotropin secretion is rapid and reversible. The suppression of pituitary LH secretion by ganirelix is more pronounced than that of FSH. An initial release of endogenous gonadotropins has not been detected with ganirelix, which is consistent with an antagonist effect.