Transsulfuration Is a Significant Source of Sulfur for Glutathione Production in Human Mammary Epithelial Cells

Figure 3

Impact of transsulfuration inhibition (PPG) on cellular total glutathione levels in human mammary epithelial cells subjected to oxidative challenge (H₂O₂). Human mammary epithelial cells (HMEC’s) were grown in normal mammary epithelial growth medium to 50% confluency and pretreated with a PBS vehicle control or propargylglycine (PPG) for 24 hours, followed by treatment in the same media with vehicle or 300 uM H₂O₂ for two hours. Cell pellets were prepared and analyzed for total glutathione levels as described under methods [45]. Results are expressed as nmol/mg of cell protein (mean ± SEM, 𝑁=5-6). Asterisk indicates a significant difference between PBS/H₂O₂ and PPG/H₂O₂ groups determined by ANOVA (𝑃<0.002).