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. Author manuscript; available in PMC: 2010 Jan 15.
Published in final edited form as: Arch Biochem Biophys. 2008 Nov 11;481(2):226–233. doi: 10.1016/j.abb.2008.10.036

Fig. 2.

Fig. 2

Effect of digitonin treatment of hepatocytes on mitochondrial membrane potential and respiration. (A) Cultured hepatocytes were loaded with TMRM to visualize mitochondria, as described in materials and methods. Red fluorescence of TMRM was imaged by laser scanning confocal microscopy. Shown are representative images of a hepatocyte before (Intact) and after consecutive treatment with 8 μM digitonin (+Digitonin), 5 mM succinate (+Succinate) and 50 μM 2,4-dinitrophenol (+DNP). As indicated by uptake of TMRM, mitochondria of intact hepatocytes partially depolarized after digitonin (+Digitonin). Succinate restored mitochondrial polarization (+Succinate), but nearly complete depolarization occurred after dinitrophenol (+DNP). Images are representative from three independent experiments. (B) Representative tracing of oxygen uptake by isolated hepatocytes incubated in ICB supplemented with 5 mM succinate after sequential addition of 50 μM dinitrophenol (DNP), 8 μM digitonin and 20 mM malonate. Inset shows respiration as a function of digitonin concentration. Data are means from six experiments. (C) Respiration of isolated hepatocytes in the absence (Intact) and presence of dinitrophenol (DNP) either with intact (None) or digitonin-permeabilized plasma membranes (Dig 8, 8 μM). Oligomycin and ATP were omitted from ICB for respiration experiments. Data are means from six experiments.