GNRH1 and hypogonadotropic hypogonadism: It is now well-established that hypothalamic kisspeptins (KPs), signaling via their cognate receptor KISS1R, are potent triggers of gonadotropin-releasing hormone (GnRH) secretion and mice bearing a deletion of the gene encoding KISS1R in the GnRH neuron display hypogonadotropic hypogonadism and infertility [1, 2].