Energetics of amino acid transport into brain slices: effects of glucose depletion and substitution of Krebs' cycle intermediates.

Amino acid uptake by slices of brain is greatly diminished by incubation of the slices in glucose-free media. Uptake can be restored by the addition of a number of substrates, e.g., lactate, citrate, or oxaloacetate. The mixture of succinate, malate, and pyruvate (SMP, 20, 5, and mM) restored amino acid uptake better than glucose after brain slices were incubated in glucose-free media to deplete endogenous energy stores. The degree of restoration of uptake was different with the various amino acid transport classes and was independent of the restoration of ATP levels in the tissue. After restoration of uptake with SMP the amino acid uptake was resistant to NaF, but was markedly more sensitive to arsenite and oligomycin. The results indicate the coupling of mitochondrial energy transducing systems to transport.