Effects of 1,1,1-trichloro-2,2-bis-(p-chlorophenyl)ethane (DDT) on ATPase-linked functions in isolated rat-liver mitochondria.

The effects of DDT on the energy-related functions of rat-liver mitochondria were examined. ADP-stimulated respiration was much more sensitive to inhibition by DDT than was uncoupler-stimulated respiration when succinate or ascorbate/TMPD was used as the substrate. Ca2+ uptake driven by ATP hydrolysis was inhibited by DDT. These results indicate that DDT inhibits ATPase itself. In addition, DDT blocked succinate dehydrogenase and the cytochrome b-c span of the electron transport chain, which also secondarily reduced ATP synthesis. The uncoupling action due to DDT was only seen at high concentrations with ascorbate/TMPD as the substrate. However, this action was masked because of the increased inhibition of the electron transport chain when the substrate was changed to succinate.