1. 1. Slices of immature rabbit brain were incubated in media utilizing as sole substrates, uniformly labeled with 14C: glucose, l-alamine, l-aspartate and glycine. In addition, slices were incubated with radioinert glucose combined with each of the labeled amino acids above. 2. 2. Only glucose supported O2 uptake above the levels found with endogenous substrate. The addition of the amino acids to the glucose-containing media did not change the rate of O2 uptake. 3. 3. The carbon skeletons of l-alanine and l-aspartate are oxidized to CO2 by developing brain at all ages studied to a significant degree. The carbon skeleton of glycine is poorly oxidized to CO2 at the same ages. The addition of glucose to each of the media containing l-aspartate and l-alanine leads to a great increase in amount of the amino acid carbon oxidized to CO2 at all ages studied. The synergistic effect of increase of l-alanine oxidation when glucose is present has not previously been noted. 4. 4. The findings of these experiments suggest the availability of some amino acids as normal or emergency substrates of oxidative decarboxylation in the developing animal brain.
Bibliographical noteFunding Information:
This investigation was supported by PHS grant number NB-o3364 (Neurological Research Center in Cerebrovascular Disease) from NINDB, and PHS grant number NB-o5oI 5.