The Origin of Plasma Proteins in Human Amniotic Fluid: the Significance of Alpha1-Antichymotrypsin Complexes

Abstract

Twelve proteins were studied in serum and amniotic fluid from 20 women in late pregnancy by 2-dimensional immunoelectrophoresis. A close inverse relationship was observed between the amniotic fluid/serum concentration ratios of 11 proteins and their Stokes radii. These proteins enter the liquor from the maternal blood by molecular filtration. The concentration of .alpha.1-antichymotrypsin in amniotic fluid was often higher than expected and the protein was often partially complexed. .alpha.1-Antichymotrypsin probably is not actively secreted into amniotic fluid but may be selectively retained after complexing.