Activities of Antioxidant and Detoxifying Enzymes in Rats after Lead Exposure

Abstract

The studies were undertaken to investigate the activity response of the antioxidant enzyme superoxide dismutase (SOD) and detoxifying enzyme glutathione-S-transferase (GST) of rats exposed to lead. Enzyme activities were determined in the liver, kidneys and heart of male and female rats that received 100 mg and 1000 mg of lead acetate per litre, respectively, in their drinking water for 18 weeks. Statistical analyses indicated differences related to the organs and to the sex of animals. Administration of lead evoked an increase of the SOD activity in the liver and kidneys both in male and female rats but only in the heart of female rats. GST activity decreased in the liver and heart of male rats, while this activity increased in the liver and heart of female rats. In kidneys, the lower lead dose resulted in a decrease of the GST activity in both groups but the higher dose evoked an increase of activity only in male rats. Thiobarbituric acid reactive substances (TBARS), an indicator of oxidative stress, significantly increased in rats that were given the high lead dose, in the kidneys of male rats and in the heart of female rats. Most probably, the observed changes could be a compensatory response to different lead accumulation in the male and female organs and also the possible distinct mechanisms in ROS elimination.