Table 4.

Specific activity of cerebral glutamine, aspartate, and alanine relative to that of glutamate after intrastriatal injection of [1-14C]pyruvate, NaH14CO3, [2-14C]pyruvate, or [1-14C]acetate

Glutamine/ GlutamateAspartate/ GlutamateAspartate/ Alanine
NaH14CO30.59 ± 0.073.5 ± 0.9
[1-14C]Pyruvate0.41 ± 0.064.0 ± 0.5*0.8 ± 0.11
[2-14C]Pyruvate0.41 ± 0.040.4 ± 0.10.5 ± 0.07
[1-14C]Acetate2.5 ± 0.3*0.3 ± 0.1
  • Anesthetized Wistar rats received 1 μCi of NaH14CO3, [1-14C]pyruvate, [2-14C]pyruvate, or [1-14C]acetate stereotactically into the striatum over 4 min, and the tissue was sampled 5 min after completion of the injection. [1-14C]Acetate was included to demonstrate the difference in labeling from a substrate that is metabolized by neurons (bicarbonate, pyruvate) and one that is metabolized by astrocytes (acetate). NaH14CO3 and [1-14C]acetate did not label alanine, hence no value for the aspartate/alanine relative specific activity. Values are means ± SEM of five to seven experiments. *Difference from the values of the other groups; p < 0.05, one-way ANOVA, Bonferroni's method for multiple comparison.