FIG. 2. Effect of mercury on SHSY5Y cellular GSH (reduced) levels. A: Changes in GSH levels over time after exposure to mercury (50 µg/L). B: Changes in GSH levels after a 30-min incubation with increasing concentrations of mercury. C: Influence of mercury (50 µg/L) after a 30-min preincubation with 1 µM melatonin. Included is a group in which melatonin and mercury (Mel + Mer) were premixed for 30 min before administration. Data are mean ± SEM (bars) values of 13 observations (from
quadruplicate independent assays). * p < 0.001, significantly different from the zero-time point for A. * p < 0.001, significantly different from the zero concentration for B. * p < 0.001, significantly different from the control and melatonin groups for C. Statistics were calculated by Mann-Whitney U test with Bonferroni's multiple comparison.