[Placental tissue concentration of pregnancy-associated proteins in early and term pregnancies].

We examined the localization of five pregnancy-associated proteins such as pregnancy specific beta 1-glycoprotein (SP1), human chorionic gonadotropin (HCG), human placental lactogen (HPL), alpha 2-PA-glycoprotein (SP3) and pregnancy-associated plasma protein-A (PAPP-A) in the placentae of early and term pregnancies by means of the PAP method in immunohistochemical technology. It was found that the degree of staining of these proteins did not reflect their concentration in serum at each gestational age. Therefore, the concentrations of these proteins in the solution extracted from the placenta were measured. 1) Placental tissues were fixed with a 10% neutral formaldehyde solution and these were embedded into paraffin blocks. These specimens were used for the PAP method. The localizations of five pregnancy-associated proteins from 10 placentae at the gestational age of 7 to 10 weeks were compared with those at the gestation age of 38 to 41 weeks from 7 patients. The staining degree of SP1 in free villi was pale in both early and term pregnancies. HCG was stained deeply in early pregnancy but pale at term pregnancy. HPL was stained deeply at both gestational ages. Horseradish peroxidase reaction products from SP1, HCG and HPL were located chiefly in the syncytiotrophoblast. SP3 was not stained on the placental tissue. PAPP-A was stained to a greater extent in the cytotrophoblast in early pregnancy but pale in the syncytiotrophoblast at term pregnancy. 2) The concentrations of SP1, HCG, HPL, SP3 and PAPP-A were measured in the placental tissues in both early and term pregnancies. Placental tissues were obtained from 24 normal pregnancy patients aborted artificially at 8 to 11 weeks gestation and from 28 patients terminated by normal deliveries at 38 to 40 weeks gestation. The tissue was homogenated with 3 volumes of 1/2 PBS (0.005M phosphate-buffered 0.07M sodium chloride, pH 7.4). The supernatant was removed after centrifugation and stored at -20 degrees C until assayed. The concentration of SP1 was measured by single radial immunodiffusion. That of HCG was assayed by a directed Latex agglutination test (Gestate Slide Eiken). The concentrations of HPL, SP3 and PAPP-A were quantified by rocket immunoelectrophoresis. No significant difference in SP1 levels was shown between early and term pregnancies, and the SP1 level was 4.3 +/- 1.3 (mean +/- 1 S.D.) mg/dl at term pregnancy. The HCG level was 1,100 +/- 300 IU/ml in early pregnancy and at least 20-fold higher than that at term pregnancy.(ABSTRACT TRUNCATED AT 400 WORDS)