The activity of glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione S-transferase (GST) was investigated in liver and kidney of rats exposed to cadmium (Cd) and ethanol (EtOH) alone and in combination. Rats were treated with 50 mg Cd/dm³ in drinking water and/or 5 g of EtOH/kg body wt/24 h intragastrically, for 12 weeks.
Exposure to Cd led to an increase in GPx and GST activity with a simultaneous decrease in GR activity in the liver. In the kidney of rats treated with Cd, an increase in the activity of GPx and GR was noted. In the EtOH-exposed rats, GPx activity decreased in the liver, but increased in the kidney. Exposure to EtOH caused a reduction in GR activity only in the liver. The co-exposure to Cd and EtOH led to an increase in the liver and kidney GPx activity compared to control. In the rats simultaneously exposed to Cd and EtOH liver activity of GR decreased compared to control, whereas the kidney GR activity increased compared to control as well as to the groups treated with Cd and EtOH seperately. The co-exposure to Cd and EtOH led to an increase in the liver activity of GST compared to the control and EtOH groups. Analysis of variance (ANOVA/MANOVA) revealed that the changes noted in the activity of investigated enzymes in the Cd + EtOH group resulted from the independent action of both Cd or EtOH as well as from their interactive action. Numerous correlations (negative or positive) were noted between the activity of GPx, GR and GST, and the concentration of GSH, Cd and MDA in the liver and kidney.
On the basis of our results it can be concluded that changes in the activity of GPx, GR and GST in the liver and kidney may be involved in the mechanism leading to a decrease in GSH concentration in these organs due to exposure to Cd and EtOH alone and in conjunction with each other.