New Role for L-Arginine in Regulation of Inducible Nitric-Oxide-Synthase-Derived Superoxide Anion Production in Raw 264.7 Macrophages

Figure 2

iNOS protein expression, nitrite accumulation, O_2•− production and expression of mRNA for NOX2 in RAW 264.7 cells. Cells were incubated in the presence of DMEM media containing 400 μM of L-arginine and stimulated with LPS (50 ng/mL). The expression of iNOS protein in cell lysates, the accumulation of nitrite, and the O_2•− production in cell supernatants (a) were determined at the time points indicated. Results represent means ± SEM (𝑛=6). (b) For NOX2, p47, and p67phox expression, cells were incubated in DMEM media with different concentrations of L-arginine (0, 100, 200, 300, and 400 μM) and stimulated with LPS (50 ng/mL) for 4 h. Results represent means ± SEM (𝑛=3). ^∗𝑃<0.05.