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

Figure 3

iNOS protein expression, nitrite accumulation, and O_2•− production in RAW 264.7 and iNOS^−/− RAW 264.7 cells. Macrophages were stably transfected with shRNA against iNOS and then stimulated with LPS (50 ng/mL). RAW 264.7 and iNOS^−/− RAW 264.7 cells were incubated in DMEM media containing 400 μM of L-arginine. iNOS protein expression in cell lysates, accumulation of nitrite (a), and O_2•− production in cell supernatants (b) were determined using methods described in Section 2 (𝑛=6). The O_2•− production was also potentate using (c) PMA and (d) OZP with or without co-administration of LPS (50 ng/mL) (𝑛=6). ^∗𝑃<0.05.