Effect of antiblastokinin on rabbit pregnancy.

On different days following coitus, i.e., during the first stages of pregnancy, adult female rabbits were treated with antiblastokinin obtained from a chicken. A high prenatal mortality was observed and a reduction of the weight in the stillborn of the rabbits treated. The antiblastokinin produces evident biological effect about the 4th day following coitus, during the period of maximum production of blastokinin by the endometrium in vivo.