Comparison of pregnancy-associated murine protein-1 and human pregnancy zone protein.

Immunological cross-reaction between human pregnancy zone protein (PZP, SP-3, alpha 2-PAG) and pregnancy-associated murine protein-1 (PAMP-1) was demonstrated by countercurrent line immunoelectrophoresis using antibodies against the proteins raised in hens. The levels of PZP and PAMP-1 were measured during pregnancy and found to be very similar in the first half of pregnancy. Both proteins were found to be heterogeneous and separable according to surface properties. It is suggested that the murine PAMP-1 can be used to study the physiology of human PZP.