Following is true about GnRH agonists except ?

Ans. is 'd' i.e., Ganirelix is the most potent agent GnRH agonists Long acting GnRH (LHRH) agonists causes reversible pharmacological orchiectomy (medical castration) and are used for precocious pubey, prostatic carcinoma, endometriosis, premenopausal breast cancer, uterine leiomyoma, polycystic ovarian disease and to assist induced ovulation. GnRH agonists have action similar to Gonadotropin releasing hormone, i.e., they increase the secretion of gonadotropins (FSH, LH). Then how do they suppress gonadol function ? Lets see. GnRH agonists increases Gn secretion. But after 1-2 weeks they cause desensitization and down-regulation of FSH/LH receptors. (continous exposure to agonist may cause down regulation of receptors) --> suppression of gonadal function. Spermatogenesis/ovulation cease and testosterone/estrogen levels fall to castration level because the action of Gonadotropins (FSH & LH) is not there (these hormones promote gametogenesis and secretion of gonadal hormones). Preparation of superactive GnRH analogues are --> Busereline, Goserelin, Leuprolide, Nafarelin, Triptorelin. Superactive/Long acting GnRH are used as nasal spray or SC injection. Cetrorelix, ganirelix and abarelix are GnRh antagonists. These are used subcutanously for the treatment of uterine fibroid & endoinetriosis and for controlled ovarian stimulation in in-vitro feilization. GnRh agonists as well as GnRh antagonists can cause hot flushes, loss of libido and osteoporosis as adverse effects.