Relationship of Metallothionein to Zinc Metabolism During Pregnancy

Abstract

The amounts of metallothionein (MT) and related substances in amniotic fluid and urine were measured, and the role of the MT contained in these fluids was studied. Amniotic fluid without blood was collected during Caesarian sections. Total urine obtained during one day was collected from newborn infants (0-6 days), and spot urine was collected from pregnant women. Sera were also collected. MT in amniotic fluid and urine was measured by radioimmunoassay. In amniotic fluid, a positive relation was observed between MT and β2-microgloblin (MG), but not between MT and zinc. In contrast, a positive relation was observed between MT and zinc in urine of newborn infants, but not between MT and MG. Serum zinc levels were significantly lower in postpartum women than healthy young women, and urinary zinc levels were markedly higher in newborn infants than healthy young women. In conclusion, the level of MT in amniotic fluid may reflect fetal renal function, and another function of MT in the fetus and newborn infant is to supplement zinc in the body.