Table 1.

Radiolabeling (dpm/mg protein) of amino acids from NaH¹⁴CO₃, [1-¹⁴C]pyruvate or [2-¹⁴C]pyruvate in primary cultures of cerebellar granule cells and astrocytes

Precursor	Specific activity	Aspartate	Glutamate	Glutamine
NaH14CO3	3.3 mCi/mmol
Granule cells		1245 ± 210	2071 ± 120	ND
Astrocytes		82.5 ± 13.0b	758 ± 133b	748 ± 40b
[1-14C]Pyruvate	13 mCi/mmol
Granule cells		6170 ± 515	550 ± 50	ND
Astrocytes		480 ± 136b	1261 ± 339	778 ± 149b
[2-14C]Pyruvate	17.5 mCi/mmol
Granule cells		23,000 ± 1960	176,630 ± 2470	5200 ± 1882
Astrocytes		4608 ± 1138b	32,896 ± 4223b	17,278 ± 26611-a

Primary cultures of cerebellar granule cells and astrocytes were incubated with NaH¹⁴CO₃, [1-¹⁴C]pyruvate, or [2-¹⁴C]pyruvate for 60 min. Radiolabeling of intracellular amino acids was determined. Values are dpm/mg protein. Mean ± SEM of four or five experiments. NaHCO₃ was 25 mm, and K⁺ was 4 mM in all experiments. ND, Not detectable.

^F1-ap = 0.01;^bp < 0.005, Student's t test; significantly different from corresponding value in granule cells.