Intraperitoneal administration of mouse kisspeptin-10 to mice during estrus stage induces pseudopregnancy.

A simple method for producing pseudopregnant mice supports pup production. In this study, pregnant ICR were obtained mice without mating with vasectomized mice via administration of mouse Kisspeptin-10 (mKp-10) and transferring blastocysts to the uterus. Blastocyst transfer after mKp-10 administration to mice with gapping and reddish pink vagina resulted in 65.2% (15/23) pregnancies, and 39.1% (34/87) of the transferred blastocysts showed full-term growth. Vaginal smears were observed for accurate estrus cycle determination, and subsequent administration of mKp10 to mice during the estrus stage and blastocyst transfer resulted in 95.2% (20/21) pregnancies and 50.7% (104/205) birth rates. Regarding 2-cell transfer after administration of mKp-10, 100% (8/8) of the mice became pregnant, and 45.0% (36/80) of the embryos were born. Administration of mKp-10 to mice during the estrus stage is a convenient way to generate pseudopregnant mice.