[Study on the properties of pregnancy-specific beta 1-glycoprotein (SP1) in urines of pregnant women (author's transl)].

The properties of pregnancy-specific beta 1-glycoprotein (SP1) were examined in urines of pregnant women. Two cross-reactive substances with rabbit antisera to SP1 were observed in the urines of pregnant woman. By agar gel immunodiffusion method two lines were formed and by single radial immunodiffusion (SRID) double rings were detected in concentrated pregnancy urines. The immunoprecipitate of the inner ring in SRID was distinct, while that of the outer ring was rather indistinct, compared with the former. The substance to make inner ring (tentatively called SP1-A) was found to be the same as SP1 in pregnant serum. The SP1-like substance to make outer ring (tentatively called SP1-B) appeared to be specific to pregnant urine. Although the precipitation lines of urinary SP1 were slightly different from that of serum SP1, both Sp1-A and SP1-B were migrated towards the beta 1-globulin region in immunoelectrophoresis. The molecular weights were estimated by gel filtration method and calculated to be 110,000 for SP1-A and 75,000 for SP1-B, respectively.