CHANGES IN GLUTATHIONE -S- TRANSFERASE LEVELS AND THIOBARBITURIC ACID REACTIVE SUBSTANCES IN ADULT AMPHIBIANS (Hoplobatrachus occipitalis and Bufo maculatus) EXPOSED TO CADMIUM

Abstract

The study evaluated changes in glutathione-S-transferase levels in the liver of Hoplobatrachus occipitalis and Bufo maculatus exposed to sub lethal concentrations (0.25, 0.50, 1.00 and 2.00mg l-1) of cadmium. Glutathione-S-Transferase (GST) levels and Thiobarbituric Acid Reactive Substances (TBARS) were determined after 28 days of exposure using the Organisation for Economic Co-operation and Development (OECD) #203 bioassay method. There were three replicate tanks per treatment and three amphibians per tank including control groups. There was a dose-dependent increase (p<0.05) in GST levels relative to controls. TBARS increased with increased cadmium concentration in both amphibians (p<0.05). The increased level of TBARS in the liver of cadmium exposed frogs was an indication of increased membrane lipid peroxidation which could lead to cell damage. The study suggests that the release of cadmium into the environment could possibly affect the well-being of anurans and cause further decline of these sensitive organisms that contribute significantly to the food web.