Fig. 8.

Effect of inhibition of the MEK-ERK1/2 pathway on the recovery of ATP production rate following TBHP-induced injury in RPTC. RPTC were treated with TBHP (0.35 mM, 45 min), and samples were taken at different time points of the recovery period to assess ATP production rate. Controls were treated with the diluent (DMSO, 0.01%). To inhibit ERK1/2 activation, RPTC were treated with 10 μM U0126 before TBHP exposure and after each daily media change starting from the media change to remove TBHP. ATP production rate was measured at 37°C in a buffer (120 mM KCl, 5 mM KH₂PO₄, 10 mM HEPES, 1 mM MgSO₄, and 2 mM EGTA, pH 7.4) containing digitonin (0.1 mg/ml), 5 mM glutamate, and 5 mM malate (electron donors to complex I) or 10 mM succinate (the electron donor to complex II) + 0.1 μM rotenone, and 2.0 mM ADP. A: ATP production coupled to complex I (using glutamate and malate as substrates). B: ATP production coupled to complex II (using succinate as a substrate). Results are average ± SE of 5 independent experiments (RPTC isolations). Values with dissimilar superscripts at a given time point are significantly different (P < 0.05) from each other.