Figure 3.

Loss of PHD enhances glycolysis and diminishes mitochondrial oxidation in PDE6-deficient retinas

Eyes from control PHD^fl/fl and PHD^−/− (homozygous for Pde6β^H620Q/^H620Q) mice were dissected at P21 before retinal degeneration. Retinas were isolated under ambient illumination, incubated with 5 mM [U-¹³C]glucose, and harvested at 30-s and 90-s time points. Metabolites were extracted with 80% methanol, derivatized, and quantified by GC-MS. Flux of carbons from [U-¹³C]glucose through glycolysis is faster in the PHD-deficient retinas, and TCA-cycle activity is slower than controls. The bar graphs in the upper-right section show that the average rates over 40 min at which glucose is consumed and at which lactate is exported are not significantly different between experimental and control retinas. Axis units are indicated in the center field, with the y axis representing picomoles or micrograms of protein and the x axis representing time (seconds). Error bars indicate SEM. ∗p ≤ 0.05, ∗∗p ≤ 0.01; n = 6–9 per group.