Search

We have previously described diminished uterine progesterone response and increased uterine sensitivity to inflammation in adult female mice with a history of developmental exposure to TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin). Since parturition in mammals is an inflammatory process mediated in part by a decline in progesterone action, toxicant-mediated disruption of progesterone receptor (PR) expression at the maternal-fetal interface would likely impact the timing of birth. Therefore, in the current study, we examined pregnancy outcomes in adult female mice with a similar in utero exposure to TCDD. We also examined the impact of in utero TCDD exposure of male mice on pregnancy outcomes in unexposed females since the placenta, a largely paternally derived organ, plays a major role in the timing of normal parturition via inflammatory signaling. Our studies indicate that developmental exposure of either parent to TCDD is associated with preterm birth in a subsequent adult pregnancy due to altered PR expression and placental inflammation., (Copyright © 2010 Elsevier Inc. All rights reserved.)

The effect of mercury (HgCl2) on placental amino acid and glucose transfer as determined by the use of their nonmetabolizable radioactive analogues, aminoisobutyric acid (AIB) and 3-o-methyl glucose (3MG), respectively, was studied in an in vitro perfusion model of a term human placenta. Hg2+ was found to decrease the transfer and accumulation of AIB without affecting 3MG transfer. It was also found to decrease the placental oxygen consumption rate. Placental circulation and tissue morphology remained intact, as demonstrated by the antipyrine transfer rate, and by electron microscopy, respectively. The mechanism by which Hg2+ may interfere with placental amino acid transfer and accumulation is discussed. Although much higher concentrations than those found in the ordinary polluted environment were used, this is the first report showing that Hg2+ interferes with an essential human placental function in a system employing a whole human placental cotyledon. This finding may indicate the possible involvement of Hg2+ in impaired organogenesis in early pregnancy or deranged fetal growth during the last trimester.