Table 1. NO^• production is dependent on L-arginine levels.

N293 cells grown with various concentrations (1, 50, 100 and 500 μM) of L-arginine were treated with 10 μM A23187 for 2 h. NO^• production was then estimated from a portion of the growth medium that was subjected to the Griess reaction assay as outlined in the Materials and methods section. Results are means±S.D. for three independent experiments.

[L-Arginine] (μM)	Nitrite (μM/h)
0	0.09±0.01
1	1.10±0.10
50	4.51±0.41
100	5.77±0.52
500	7.16±0.64