RESUMO
Cadmium is known to be an environmental and industrial pollutant. Exposure to cadmium is known to affect various tissues. The purpose of this study is to determine the toxic effects of cadmium on lactate dehydrogenase (LDH) isoenzymes. Administration of cadmium chloride (3 mg kg-1) resulted in the reduction of LDH4 fraction of liver tissue indicating the inhibitory effect of cadmium. The LDH1, LDH3 and LDH5 fractions showed decreasing trend initially but there was a significant increase later. In contrast the LDH2 fraction showed increasing trend after 24 hr from the last dosage it was elevated after 30 days. The total activity of LDH in liver showed gradual reduction in both groups. The activity of succinate dehydrogenase (SDH) the mitochondrial enzyme has been observed to be inhibited by cadmium with the possibility of interfering with energy transport mechanism. Na+- K+ - ATPase activity of liver also showed similar decrease after cadmium administration which may lead to general deficit in cell membrane transport. As cadmium shows drastic decrease in all the enzymes studied, the LDH2 fraction which sharply rises from the control may be used as a marker enzyme to asses the liver injury.