Effect of chlordane on hepatic mitochondrial respiration

In order to clarify the cytotoxicity of chlordane, an industrial product used as an insecticide, its effect on oxidative phosphorylation in rat hepatic mitochondria was studied. The respiration rate, RCI and ADP/O ratios were inhibited by chlordane-related compounds; the degree of inhibition was in the descending order of trans-chlordane, cis-chlordane, heptachlor and heptachlorepoxide. Of the indices indicating various respiratory activities, state 3 respiration was the most sensitively inhibited by these compounds, suggesting that they inhibit energy transfer. However, electron transport was inhibited also by high concentrations of chlordane constituents. The inhibitory effect of the chlordane constituents on respiratory activity varied depending on the species of respiratory substrate, suggesting site-specificity of these compounds. The release of K+ ions paralleled the results of the respiratory activity study. Heptachlorepoxide, a metabolic product of heptachlor, had less effect on mitochondria than heptachlor.