Macnaha qaamuuska ereyga "fasaxa sii deynta" waxaa loola jeedaa hormoon ama walax kicinaysa sii deynta hormoonka kale ee qanjirka pituitary. Gaar ahaan, arrimaha sii daaya waa farriimaha kiimikaad ee ay soo saarto hypothalamus waxayna u dhaqmaan qanjirka hore ee pituitary si ay u kiciyaan sii deynta hormoonnada sida hoormoonka koritaanka, hormoonka tayroodh-kicinta, iyo hoormoonka follicle-stimulating. Erayga "wax sii daynta" waxa kale oo loo isticmaali karaa si ballaadhan si loo tixraaco walax kasta oo kiciya sii daynta walax kale ama hawl kale.