Figure 13. The inhibitory effects of DPI on mitochondrial respiration are reversible. To assess the reversibility of DPI’s effects after drug removal, MCF7 cells were first subjected to DPI treatment for 24 hours. Then, the DPI was removed by washing with normal media and the cells were cultured for an additional 24 hours to allow them to recover. This cycle of DPI-treatment, “wash-out” and recovery was carried out over a concentration range of 10 to 50 nM DPI. Note that with 10 nM DPI, there was a near complete recovery of basal respiration, after only 24 hours. Higher concentrations (25 and 50 nM) still showed significant recovery, but the recovery was not complete at this time point.