Observations on the origin of pregnancy-associated plasma proteins

Abstract

1. The “alpha-2 globulin of pregnancy” has been found in the sera of nonpregnant females and in increased amounts in trophoblastic disease, during pregnancy, and during the administration of Enovid. The placenta, therefore, is not essential to the synthesis of this protein.2. The pregnancy-associated phosphatase and two cystine aminopeptidases, not being observed in patients with trophoblastic disease or during the administration of Enovid. seem to be specific for pregnancy. Since they are also absent from fetal blood, the placenta is the probable site of origin of these enzymes.3. Both Enovid administration and trophoblastic disease elicit the appearance of other aminopeptidase bands. one of which is similar in mobility to one of the pregnancy-associated cystine aminopeptidases. It can be differentiated from it by means of incubation with neuraminidase.4. The possibility of further development of the zymogram technique for the differentiation of trophoblastic disease and pregnancy is discussed.