Fig. 2.

Impact of Arg·Glu and other salts on THP-1 cell nitric oxide production

THP-1 cells were seeded into 24-well plates at 10⁶ cells/mL in serum free RPMI media and were cultured for 24 h at 37 °C in medium alone (represented by the dashed line) or in the presence of 50 mM (open column) or 100 mM (closed column) Arg·Glu, NaCl, Arg·HCl or NaGlu. Supernatants (A) and lysates (B) were collected after the 24 h incubation and the nitrite concentration was determined by the Griess assay. The nitric oxide content of the media (with supplements) in the absence of cells was also determined (dotted line). The nitrite concentrations were determined using a nitrite standard reference curve and the associated computer software for microplate-based assays and data are displayed as nitrite concentration (μM; mean and SE). The statistical significance of differences in the nitrite content of samples from cells cultured in medium alone and cells treated with various concentrations of salts was assessed by one way ANOVA (*p < 0.05).