<prompt> GnRH analogue may be given in all of the following exceptProstate CaEndometrium CaFibromyoma - uterusPrecocious pubey  <response>: Ans. is b i.e Endometrial Ca GnRH agonist : Mechanism of action : GnRH agonist bind to GnRH receptors in the pituitary, and cause competitive inhibition of endogenous GnRH. Initially there is a supraphysiological release of FSH and LH from pituitary Flare followed by decrease in the synthesis and release of both FSH and LH. Preparations of GnRH : Buserelin Leuprorelin Nafarelin Gosserelin Triptorelin Historelin Method of administration : Subcutaneousintramuscular injections or as nasal sprays. Indications : In females : In all those conditions where there is increased estrogen, GnRH analogues are useful. Mnemonic : A - F and HIP. A Adenomyosis B Irritable Bowel Syndrome under Trial C Ca Breast Tamoxifen GnRH agonist give good result D DUB E Endometriosis F Fibromyoma uterus. H Hirsutism I Infeility P Precocious Pubey. In males : Cryptorchidism : sho term intranasal nafarelin is used. Carcinoma prostrate : GnRH agonist are as effective as orchidectomy in Ca prostrate but if there are neurological symptoms or life threatening metastatic disease - androgens should first be staed followed by GnRH agonist. BPH : Daily administration of leuprorelin or nafarelin decreases obstructive urinary symptoms in 1-6 months time. Adverse effects of GnRH : Local allergic reaction may occur at injection site. They cause menopause like Symptoms -- Hot flushes, vaginal dryness, headache, joint and muscle stiffness, depression, osteoporosis and irregular vaginal bleeding. GnRH antagonist : Acts immediately to stop Gonadotropin secretion without any flare eg : Cetrirelix, Ganirelix, Nal-glu. They have been superceeded by GnRH agonist in clinical practice except for their potential role in Contraception. Nal-glu given for 3 weeks inhibits spermatogenesis 