Demonstration of analogues to the human pregnancy zone protein in animals.

The pregnancy zone protein (PZ) is known to occur in increased amounts during pregnancy and hormonal treatment. Analogues of this human serum alpha2-globulin were demonstrated in animals by double gel diffusion and immunoelectrophoresis. Direct cross-reactions were found for Rhesus monkey and beagle dog against anti-human pregnancy zone protein. After preparation of an "anti-dog PZ" serum it was possible to demonstrate analogues also in cow and sheep. Thus, the present investigation demonstrated animal analogues to the human pregnancy zone protein, which should be valuable for studies of the biological role of this protein.