The kisspeptin gene (Kiss1) is knocked out conditonally by the Cre recombinase. This strain was generated by K.I. Maeda (The University of Tokyo), H. Tsukamura, Y. Uenoyama, N. Inoue (Nagoya University), and M. Hirabayashi (National Institute for Physiological Sciences) for the purpose of producing conditional knockout rats of the Kiss1 gene in the hypothalamus. The targeting vector (loxP, Kiss1[exons 2 and 3], PGK promoter-neo, loxP) was introduced by electroporation targeting the Kiss1 gene in ES cells (WDB/Nips-ES1/Nips). Crossed with and maintained by the Wistar-Imamichi rats (Iar:Wistar-Imamichi, Institute for Animal Reproduction).