Trace metals and metalloenzymes in placenta after oral administration of lead acetate.

The present study was carried out to find the effects of Pb acetate (10-50 mg/kg body wt) after oral administration on: 1. The distribution of elements, such as Fe, Cu, Zn, and Mn; 2. The activity of 6-amino levulenic acid dehydratase (delta-ALAD) and alkaline phosphatase (PAP); and 3. On the level of reduced glutathione (GSH) in murine placenta. Pb toxicity expressed on a dry-wt basis was reflected in terms of deficiency of delta-ALAD and PAP and enhanced content of GSH. Analysis of trace elements following Pb exposure showed low levels of Mn and Cu. Although Fe composition of placenta remained within normal range with increasing load of endogeneous Pb, Zn decline was not consistent after oral feeding of Pb acetate. Deficiency of PAP after Pb exposure did not correlate with the endogeneous levels of Pb or Zn therein, but correlated with endogeneous levels of Mn. Placental deficiencies of Cu and Mn have been related to the disturbed placental functions by Pb accumulation.