Fig. 3. Reduction of MTT in cells overexpressing aralar1 or citrin. Digitonin (20 µM)-permeabilized HEK-293T cells overexpressing aralar1 (filled bars) or citrin (striped bars) or the empty pIRES vector (open bars) were tested for reduction of MTT in the presence of either 1 mM glutamate, 5 mM malate and 10 mM lactate (G + M + L) or 15 mM glycerol-3-phosphate and 10 mM lactate (G-P + L). Under basal conditions, no substrates were added. (A) Reduction of MTT in the presence of various substrates. (B and C) Normalized MTT reduction. The results (means ± SEM) correspond to a representative experiment performed four times. The differences between controls and cells overexpressing aralar1 or citrin were significant (*P <0.05, ***P <0.001, one-way ANOVA and Bonferroni t-test).