Glutamine Is Essential for Nitric Oxide Synthesis by Murine Macrophages

Modulation of Macrophage Nitric Oxide Production by Prostaglandin D2

“…Consistent with previous work done in our laboratory, as well as work of other investigators [7,15], we have shown that RAW 264.7 macrophages exposed to LPS produce nitric oxide in a dose-dependent manner. The present work also demonstrates that exogenous PGD 2 causes a significant reduction in the amount of LPS-induced nitric oxide produced by macrophages in a dose-dependent fashion.…”

“…In the second set of experiments, the macrophages were exposed to varying doses of PGD 2 added before or after stimulation with 0.01 or 1.0 g/ml LPS for a 24-h incubation period at 37°C. The two doses of LPS were chosen based on a previous study [15]. In the third set of experiments, macrophages were exposed to indomethacin (10 ⌴) 1 h before LPS stimulation and then incubated for 24 h.…”

“…The absorbance was recorded at 540 nm on a Beckman DU640 spectrophotometer. A standard curve for quantitation of nitrite production was constructed using serial dilutions (5,10,15,20,25,30, and 35 nmol/ml) of sodium nitrite (Sigma Chemical, St. Louis, MO). Results are expressed as nanomoles of nitrite released by 1.1 ϫ 10 6 cells per 24 h. For all experiments, the nitrite activity of the untreated wells was subtracted from all measurements to eliminate baseline nitrite content.…”

Time course of nitric oxide production after endotoxin challenge in mice

“…The role of Gln in NO production during sepsis is still not completely understood. Besides its conversion to Cit in the intestine, Gln may also act as an Arg precursor and a regulator of NO synthesis in LPS-activated cells (4). Increased levels of plasma Gln and Wb Gln production simultaneous with the late endotoxemia NO peak, in the current study, corroborate the notion that Gln might be required to sustain NO production.…”

A guide to immunometabolism for immunologists

“…Glutamine metabolism is also important for the generation of nitric oxide through feeding into arginine synthesis 67 , demonstrating a role for glutamine in the cytotoxic and antimicrobial functions of macrophages. Indeed, pharmacological inhibition of glutaminase activity or glutamine withdrawal from culture medium resulted in decreased nitric oxide production by bacille Calmette-Guérin (BCG)-activated macrophages in vitro 67,68 . Interestingly, recent work has shown that glutamine is extensively fluxed into the TCA cycle and the hexosamine pathway and promotes M2 macrophage polarization in response to IL-4 stimulation, whereas LPS-stimulated M1 macrophages do not require glutamine for their development 25 .…”