"Blastokinin": Inducer and Regulator of Blastocyst Development in the Rabbit Uterus

A protein fraction that induces blastulation of rabbit morula and stimulates blastocyst development has been isolated from the uterus of the rabbit at early pregnancy. Partial purification of this fraction indicates that the activity is restricted to a single homogeneous protein component. The term "blastokinin" is proposed to describe the compound.