Table 3.

Intracellular concentrations of L-citrulline and L-arginine in unstimulated and LPS/IFN-γ-stimulated aortic smooth muscle cells

Amino acid	Control	Control(−L-arginine)	LPS+IFN-γ	LPS+IFN-γ(−L-arginine)
L-arginine (mM)	1.43±0.36	0.26±0.01*	0.76±0.10	0.30±0.03⧫
L-citrulline (mM)	0.16±0.03	0.49±0.29	3.19±0.11*	0.04±0.04⧫

Unstimulated and activated aortic smooth muscle cells (100 μg ml⁻¹ LPS+50 U ml⁻¹ IFN-γ, 24 h) were extracted and intracellular L-arginine and L-citrulline concentrations determined by reverse-phase hplc. Results are expressed as intracellular amino-acid concentration (mM) assuming an intracellular water space of 1 pl. Data denote the means±s.e.m. of determinations in three different cell cultures.

^*P<0.05 versus control

^⧫P<0.05 versus LPS+IFN-γ.