Gonadotropin-releasing hormone (GnRH), also known as follicle-stimulating hormone–releasing hormone (FSH-RH), luteinizing hormone–releasing hormone (LHRH), gonadoliberin, and luliberin in its endogenous form and as gonadorelin (INN) in its pharmaceutical form, is a releasing hormone responsible for the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary. GnRH is a tropic peptide hormone synthesized and released from GnRH neurons within the hypothalamus. The peptide belongs to gonadotropin-releasing hormone family. It constitutes the initial step in the hypothalamic–pituitary–gonadal axis.