TRANSPLACENTAL KINETICS OF LEAD IN PREGNANT MINIPIGS

This study examined the maternal and fetal blood kinetics of lead in p regnant, near term mini-pigs. A lead dose of 1 mg/kg was administered to the animals by i.v. injection as bolus. During the 5-h sampling per iod, the two-compartment maternal pharmacokinetics demonstrated a rapi d phase T-1/2 of 8 min and a slower phase T-1/2 of 199 min. Lead reach ed the fetus with a time lag of 81 min. At 24 h after administration t he ratio of fetal to maternal blood lead concentration seemed to becom e stable. When lead was injected directly into the fetal blood circula tion, the decay of fetal blood lead fitted a one-compartment model. Th e disappearance half-life was 92 min. Lead can obviously accumulate in fetal liver; the lead level in fetal brain showed no detectable chang es. This study confirmed that lead can also pass through the epithelio chorial placenta.