EFFECT OF THERMAL-STRESS ON GLUTATHIONE METABOLISM IN HUMAN ERYTHROCYTES

This is the first experiment to investigate the effect of heat and col d stress on glutathione metabolism in human erythrocytes. We immersed men at three different water temperatures for 10 min. At 39 degrees C, no remarkable changes were observed. Levels of glutathione (GSH) decr eased from 2.44 (0.14) to 1.80 (0.10) mu mol.ml red blood cells(-1) [m u mol.ml RBC(-1); mean (SEM); P<0.0005] and those of lipid peroxides i ncreased from 1.87 (0.03) to 2.06 (0.03) nmol.ml RBC(-1) (P < 0.01) af ter the immersion at 42 degrees C. In contrast, levels of GSH increase d from 2.46 (0.17) to 2.91 (0.17) mu mol.ml RBC(-1) (P<0.05) and those of lipid peroxides did not change after the immersion at 25 degrees C . The activities of glutathione peroxidase decreased from 35.90 (1.83) to 34.33 (1.66) IU g Hb(-1) (P < 0.01) after the immersion at 42 degr ees C; however, these activities did not change after the immersion at 25 degrees C. The activities of glutathione reductase (both active an d inactive forms) showed no changes at any temperatures. These changes indicate that heat stress causes oxidative stress in the human body; however, cold stress is thought to augment the activity of the antioxi dative defence system. It is suggested that body exposure to hot envir onmental conditions should not be recommended for patients suffering f rom a damaged antioxidative defence system.