▁Or gal ut ran ▁and ▁An tagon ▁ ▁among ▁others , ▁is ▁an ▁inject able ▁compet itive ▁g on ad otrop in - re le asing ▁h orm one ▁ant agon ist ▁( G n R H ▁ant agon ist ). ▁It ▁is ▁primarily ▁used ▁in ▁assist ed ▁reprodu ction ▁to ▁control ▁ov ulation . ▁The ▁drug ▁works ▁by ▁blocking ▁the ▁action ▁of ▁G n R H ▁upon ▁the ▁p itu it ary , ▁thus ▁rapidly ▁suppress ing ▁the ▁production ▁and ▁action ▁of ▁L H ▁and ▁F SH . ▁Gan ire li x ▁is ▁used ▁in ▁fert ility ▁treatment ▁to ▁prevent ▁prem ature ▁ov ulation ▁that ▁could ▁result ▁in ▁the ▁har vest ing ▁of ▁eggs ▁that ▁are ▁too ▁imm ature ▁to ▁be ▁used ▁in ▁procedures ▁such ▁as ▁in ▁vit ro ▁fert il ization . ▁ ▁G n R H ▁ag on ists ▁are ▁also ▁sometimes ▁used ▁in ▁re product ive ▁ther apy , ▁as ▁well ▁as ▁to ▁treat ▁dis orders ▁involving ▁sex - st ero id ▁h orm ones , ▁such ▁as ▁end omet rios is . ▁One ▁advantage ▁of ▁using ▁G n R H ▁ant agon ists ▁is ▁that ▁repeated ▁administration ▁of ▁G n R H ▁ag on ists ▁results ▁in ▁decre ased ▁levels ▁of ▁g on ad otrop ins ▁and ▁sex ▁ster oid s ▁due ▁to ▁des ens it ization ▁of ▁the ▁p itu it ary . ▁This ▁is ▁avoided ▁when ▁using ▁G n R H ▁ant agon ists ▁such ▁as ▁gan ire li x . ▁The ▁success ▁of ▁gan ire