Human serum Zn-alpha2-glycoprotein in amniotic fluid.

Human serum Zn-alpha2-glycoprotein (Zn-alpha2-GP) was found to be present in the amniotic fluid in the mean concentration of 0.98 +/- 0.40 mg/100 ml, which represents about one-tenth of its concentration in the maternal serum (9.65 +/- 1.18 mg/100 ml). Its concentration in the amniotic fluid was proportional to the amniotic fluid total protein and very approximately to the maternal serum Zn-alpha2-GP. The relationship between the maternal serum Zn-alpha2GP and the maternal serum total protein as well as between the amniotic fluid total protein and the maternal serum total protein was found to be not significant. The amniotic fluid Zn-alpha2-GP as well as the amniotic fluid total protein showed some increase during gestation to reach the highest values at the end of the second trimester. At present both the origin and significance of the amniotic fluid Zn-alpha2-GP are not known.