GNRH1 and Infertility: Known for its involvement in the transmission of pain and proinflammatory stimuli, SP may also influence hypothalamic GnRH secretion, in this way indirectly modulating pituitary and gonadal activities: while on the one hand SP deficiency led to delayed sexual maturation and/or to infertility in females [39], on the other hand the activation of NK1 receptor by SP during the prepubertal period accelerated the onset of sexual maturation, possibly through early activation of kisspeptin-containing neurons [39].