The hepatic enzyme glutathione s-transferase (GST) plays an important role in the body by detoxifying xenobiotics and can serve as a biomarker for toxicity of certain chemicals. The goal of this study was to establish a response in GST activity upon exposure to different treatments in the HepG2 cell line. We hypothesized that treatment with the heavy metal cadmium, and the hormones vitamin D, estrogen, and dexamethasone would induce a change in GST activity in the human liver cell line, HepG2. We conducted an MTT assay to determine if the treatments affected cell viability. We found that treatment with 10uM cadmium significantly decreased cell viability, while all other treatments showed no significant effect on cell viability. GST activity was determined by measuring how much GSH was conjugated per sample. Our results demonstrated that each of the treatments significantly suppressed GST activity compared to controls. These findings suggest that these compounds may be inhibiting GST expression and/or activity in some way, resulting in an inability to perform its necessary detoxifying function. Evidence suggests that flavonoid compounds exhibit antioxidant properties and we hypothesize that they are acting through an induction of GST. We are currently working to determine whether co-treatment of cells with sagebrush extracts will restore GST activity to control levels due to the flavonoid compounds found in sagebrush.

Xenobiotics Alter Glutathione S-Transferase Activty In Hep G2 Cells