Glutathione S-transferase isoenzymes in decidua and placenta of preeclamptic pregnancies

Objective: To investigate a possible involvement of glutathione S-transferases, major detoxificating enzymes, in the pathophysiology of preeclampsia. Methods: Levels of glutathione S-transferase isoforms and enzyme activity were assessed in placental and decidual tissues in 22 preeclamptic and 21 normotensive women. Measured values were analyzed statistically using the Mann-Whitney U test for comparison between groups, and the signed-rank test for comparison within groups. Results: Glutathione S-transferase pi is the main glutathione S-transferase isoform in normal placental and decidual tissue. Lower median placental and decidual glutathione S-transferase pi levels were found in preeclamptic women compared with controls: 1268 (range: 524-3925) and 2185 (range: 503-6578), P = .05, for placenta; 1543 (range: 681-2967) and 2169 (range: 893-3929), P =.02, for decidua. The total amount of glutathione S-transferases in control and preeclamptic pregnancies was higher in decidua than in placenta. Conclusion: Reduced levels of glutathione S-transferase class pi in preeclampsia might indicate a decreased capacity of the glutathione/glutathione S-transferase detoxification system. A higher total amount of glutathione S-transferases in decidual tissue might point to a more pronounced protective role of decidua compared with placenta. (Obstet Gynecol 1999;94:1033-8. (C) 1999 by The American College of Obstetricians and Gynecologists.).