TAC3 and hypogonadotropic hypogonadism: Clinical studies also demonstrated the involvement of neurokinin B, a member of tachykinin family (83), in regulation of GnRH/gonadotropin secretion and pubertal onset in humans: loss-of-function mutations of TAC3 gene (coding neurokinin B) or TACR3 gene (coding tachykinin NK3 receptor (NK3R), which preferably bind to neurokinin B) also caused hypogonadotropic hypogonadism and pubertal failure in humans (84–86).