ACTIVITY OF GLUTATHIONE-PEROXIDASE AND SUPEROXIDE-DISMUTASE IN WORKERS OCCUPATIONALLY EXPOSED TO MERCURY

According to previous research the lipid peroxidation process has a si gnificant role in mercury toxicity. Since glutathione peroxidase (GPX) and superoxide dismutase (SOD) play a significant role in erythrocyte antioxidative defence, it is very important to determine their activi ty in occupationally exposed workers. The aim of this study was to ass ess the activity of antioxidative enzymes in the erythrocytes of worke rs occupationally exposed to mercury. We compared a group of 42 worker s exposed to elemental mercury in a chloralkali plant (Hg group). The control group (C group) consisted of 75 subjects employed in lime prod uction who had never been exposed to mercury or any toxic substance. T he GPX activities in erythrocytes were significantly lower in the Hg g roup than in the control group (Hg group, 9.05 +/- 7.52 IU/gHb; C grou p 15.54 +/- 4.85 IU/gHb; p < 0,001). Also, SOD activity in the erythro cytes of workers occupationally exposed to mercury was significantly l ower than in the control group (Hg group, 1280.7 +/- 132.3 IU/gHb; C g roup, 1377.9 +/- 207.5 IU/gHb; p < 0.006). The concentrations of mercu ry in blood were significantly higher in the Hg group compared to the control group (Hg group, 0.179 +/- 0.040 mu mol/l; C group, 0.023 +/- 0.011 mu mol/l; p < 0.001). Urine mercury concentrations were also sig nificantly higher in the Hg group than in the control group (Hg group, 23.2 +/- 11.3 nmol/mmol creatinine; C group, 2.7 +/- 0.6 nmol/mmol cr eatinine; p < 0.001). The concentrations of selenium in erythrocytes w ere almost equal in both groups examined (Hg group, 62.9 +/- 8.72 mu g /l; C group, 65.8 +/- 10.57 mu g/l) Also, in the Hg group there were i ncreased levels of erythrocyte malondialdehyde (Hg group, 138.58 +/- 3 3.85 mu mol/l; C group 105.21 +/- 49.62 mu mol/l; p < 0.001). On the b asis of previous results, it can be concluded that occupational exposu re to elemental mercury leads to increased lipid peroxidation in eryth rocytes. Also, it can be postulated that this exposure leads to decrea sed activity of GPX and SOD in erythrocytes.