Acidosis-induced effects are sensitive to NAD redox state and reversible. (A) After incubation at pH 6.5 for 1 hour, NAD(P)H signal was significantly higher in PTs in kidney slices incubated in lactate (10 mM) than in pyruvate (10 mM) (n=22 PTs from four different slices, from two different animals). P<0.01 for lactate versus pyruvate after Mann–Whitney U test. Conversely, vacuole formation (arrows) was significantly lower in lactate incubated tissue (n=6–7 different slices from three to five different animals). P<0.05 for lactate versus pyruvate after Mann–Whitney U test. (B) After 1 hour of acidosis, increasing pH back to 7.4 caused an increase in mitochondrial NAD(P)H signal (n=14 PTs from nine different slices from five different animals; P<0.01 for pH 6.5 versus pH 7.4 after paired t test) and disappearance of lipid vacuoles (arrow) (n=7 PTs from seven different slices from five different animals; P<0.01 for pH 6.5 versus pH 7.4 after paired t test). a.u., arbitrary units.