A method for the separate measurement of the beta- and alpha-components of SP1 in pregnancy serum

Postpartum decline in serum concentration of placental proteins in an abdominal pregnancy

The alpha and the beta forms of Schwangerschaftsprotein 1 (SP1) and chorionic gonadotrophin (hCG) were measured after delivery in an abdominal pregnancy with the placenta left in situ. All three proteins declined more slowly than after normal delivery; the half-lives ranging from 6.2-6.5 days. Traces of the proteins could still be detected in the maternal circulation 9 weeks after delivery. These findings are construed as further support for the belief that the placenta plays a major role in the synthesis of these proteins.

Periovulatory secretion of immunoactive pregnancy-specific beta 1-glycoprotein (SP1) in humans: comparison with "normal" SP1

The pregnancy-specific beta 1-glycoprotein (SP1)-immunoreacting material in serum from two patients around ovulation was compared with serum SP1 activity derived from normal pregnant women. This was done by antibody binding experiments, density gradients and binding to lentil lectin. Periovulatory SP1 behaved similarly to SP1 from pregnant patients. It is therefore suggested that the periovulatory immunoreacting material is true SP1 and that this protein, though rarely, can be synthesized outside the trophoblast in healthy women.

Determination of the stage of gestation by the assay of chorionic gonadotrophin and Schwangerschaftsprotein 1

Serial assays of Schwangerschaftsprotein 1 (SP1), SP1 alpha, SP1 beta and human chorionic gonadotrophin were performed in 12 subjects from ovulation until the pregnancies had reached 16 weeks. From these data formulae were devised for deducing the stage of gestation from the concentration of the placental protein. These formulae were then tested by assays on 34 women not included in the original study. Assays of hCG do not give reliable indications of the stage of gestation when this has progressed beyond 9-10 weeks but SP1 assays give predictions of gestation corresponding closely to that derived from the last menstrual period up to 16 weeks gestation.

Studies on the half-life of Schwangerschaftsprotein 1 (SP1)

Schwangerschaftsprotein 1 (SP1) was measured in 10 women at intervals after delivery of the placenta. SP1 alpha decreased more sharply than SP1 beta and showed evidence of a two-compartmental distribution in the mother. Trace amounts of both proteins could still be detected 5 weeks after delivery. It is concluded that the findings support the view that the two proteins are separate biological entities and that there is a possibility that SP1 beta is generated from SP1 alpha in the maternal compartment.

The concentrations of SP1 beta and SP1 alpha in retroplacental and peripheral blood at term

The concentrations of the two components of Schwangerschaftsprotein 1 (SP1 beta and SP1 alpha), human chorionic gonadotrophin (hCG) and human placental lactogen (hPL), were measured in peripheral venous blood and in retroplacental blood at term delivery in 22 women. Like hCG and hPL, the values of SP1 alpha were higher in the retroplacental than in the peripheral blood, as might be expected with placental secretory products. On the other hand, the concentration of SP1 beta showed a reverse gradient, being higher in the peripheral than in retroplacental blood.

Diagnosis of early pregnancy by assay of placental proteins

The plasma concentrations of Schwangerschaftsprotein 1 (SP1) and human chorionic gonadotrophin (hCG) were measured in 22 women before and after conception. In these pregnancies ovulation occurred spontaneously in seven subjects, or followed treatment with either clomiphene citrate (6 subjects), or human menopausal gonadotrophin (hMG) and hCG (6 subjects). The remaining three patients became pregnant after artificial insemination with donor semen. Seventeen of these pregnancies were normal and five were abnormal (3 abortions, 1 ectopic and 1 twin). SP1 could be detected 6-14 days after ovulation in all these patients. In contrast 40 non-pregnant women gave a negative test for SP1.

Complex formation of pregnancy-specific alpha 2-glycoprotein (SP1 alpha) and heparin

The Schwangerschaftsprotein 1 (SP1)alpha values in blood measured by rocket immunoelectrophoresis are affected by the addition of anticoagulants. When compared with values in serum, those in heparin plasma were much higher, while those in sequestrene ethylenediamine-tetra-acetic acid), sodium citrate and fluoride oxalate were lower. On the other hand, SP1 and SP1 beta concentrations were not significantly affected in heparin or sequestrene and were only slightly depressed in sodium citrate and fluoride oxalate. The effect of heparin on SP1 alpha in serum was dose-dependent. We surmise that SP1 alpha forms a complex with heparin and that it may be involved in the coagulation system in pregnancy.