RESUMO
A study of placental detoxifying activity was undertaken using as the investigated indices glutathione transferase and glutathione reductase activities and total amount of SH-groups and those of low-molecular weight thiols. Malonic dialdehyde content was used as a measure of lipid peroxidation. The placental samples were obtained in several regions of the Ukraine judged either "clean", chemically polluted or radioactively contaminated. In the samples from the "clean" region glutathione transferase and glutathione reductase activities as well as the total amount of SH-groups were higher than corresponding indices in ecologically unfavorable regions of the Ukraine. At radioactively heavily exposed women low glutathoione transferase activity combined with low content of SH-groups and pronounced increase of malonic dialdehyde. In the regions with the lower summary effective equivalent annual expositional doses the indices of placental glutathione status are more close to those characteristic for placenta from "clean" regions. The consequences of the more intensive but short exposure characteristic for the women evacuated from Pripyat on the second day after catastrophe were less manifest in the indices of the glutathione status. A decrease of glutathione transferase activity at chemically exposed women was in the range of the lowest values obtained for heavily radioactively exposed ones but differ by higher content of total SH-groups and low molecular weight thiols. The glutathione transferase activity of cytosol from the samples of chemically exposed women increased in vitro after their treatment with the reducing agent. More probable the different mechanisms underlie the similar reduce of glutahtione transferase activity in radioactively contaminated and chemically polluted regions of the Ukraine. The decreased activity of glutathione transferase activity in placenta correlated with the increased frequency of complications during the pregnancy and the delivery and with the worsening status of newborns.
