The metabolism of glucose and pyruvate in rat retina

The metabolism of [U-$^{14}$C] glucose and [3-$^{14}$C] pyruvate in the adult rat retina is described. In vitro under aerobic conditions, in either phosphate or bicarbonate medium, glucose was converted into lactate, carbon dioxide, glutamate, $\gamma $-aminobutyrate, aspartate, glutamine and alanine. Under anaerobic conditions, total glucose metabolized was reduced to 60 to 70% of that under aerobic conditions, lactic acid being the only metabolic product detected. Under aerobic conditions [3-$^{14}$C]pyruvate was converted by the retina into the same metabolites as was glucose. The quantitative data for oxygen uptake and $^{14}$CO$_{2}$ formation were similar to those obtained with glucose as substrate; lactate production was lower and amino acid formation higher.