Abstract

Lipoperoxide concentration in erythrocytes from workers occupationally exposed to lead (mean blood lead concentration 57.1 (SD 17.6) micrograms/dl) was significantly higher than that in controls. It was not different in plasma from the two groups. The activity of superoxide dismutase (SOD) and catalase in erythrocytes from workers exposed to lead was significantly lower than that of control subjects. The effect of lead was also seen in the glutathione concentration of erythrocytes from lead exposed workers, which was reduced to 69% of that found in erythrocytes from control workers. The increase in methaemoglobin content of erythrocytes from workers exposed to lead was less than expected and not significantly different from that of controls. A positive correlation between lipoperoxide concentration in erythrocytes and lead concentration in blood and a negative correlation between glutathione concentration in erythrocytes and blood lead concentration were found. Incubation of erythrocytes for 24 hours at 37 degrees C in the presence of lead (100 micrograms/dl) produced no changes in glutathione and lipoperoxide concentrations, although there was inhibition of activity of SOD (14.3%), catalase (10.1%), and glutathione peroxidase (35.1%). A similar experiment with heparinised whole blood showed increased haemolysis with no changes in membrane lipid peroxidation of erythrocytes. It is postulated that the lowered concentration of glutathione and decreased activity of SOD, catalase, and glutathione peroxidase in erythrocytes from workers exposed to lead may play a part in the increased membrane lipid peroxidation. Furthermore, the results suggest the possibility that leucocytes, or platelets, or both, may induce haemolysis in the presence of lead.