Ganirelix Acetate Peptide API

The pulsatile release of gonadotropin-releasing hormone (GnRH) stimulates the synthesis and secretion of LH and FSH. The frequency of LH pulses in the mid and late follicular phases is approximately 1 per hour. These pulses are reflected in transient rises in serum LH. During mid-menstrual period, the massive release of GnRH causes a surge of LH. The midmenstrual LH surge can trigger several physiological responses, including: ovulation, oocyte meiotic resumption, and corpus luteum formation. The formation of the corpus luteum causes serum progesterone levels to rise, while estradiol levels fall. Ganirelix acetate is a GnRH antagonist that competitively blocks GnRH receptors on pituitary gonadotrophs and subsequent transduction pathways. It produces a rapid, reversible inhibition of gonadotropin secretion. The inhibitory effect of ganirelix acetate on pituitary LH secretion was stronger than that on FSH. Ganirelix acetate failed to induce the first release of endogenous gonadotropins, consistent with antagonism. Complete recovery of pituitary LH and FSH levels occurred within 48 hours after ganirelix acetate was discontinued.