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. Author manuscript; available in PMC: 2013 May 15.
Published in final edited form as: Nitric Oxide. 2012 Mar 14;26(4):217–222. doi: 10.1016/j.niox.2012.03.003

Figure 2.

Figure 2

Nitrate-Nitrite-Nitric Oxide Formation/Recycle Pathways.

In the presence of oxygen endothelial nitric oxide synthase (eNOS) catalyzes the oxidation L-arginine to NO. NO can exhibit biological effects and has been shown to increase tissue perfusion along with angio- and arteriogenesis in PAD models. NO may also be rapidly oxidized to nitrite (NO2−) and nitrate (NO3−). A secondary source of vascular NO is via diet. Consumption of food stuffs high in inorganic nitrate (green leafy vegetables, beetroot) have been shown to increase plasma nitrate which can be secreted in saliva and reduced to nitrite by commensal bacteria in the mouth. Nitrite can then be further reduced to NO (and other biologically active nitrogen oxides) via several mechanisms which are expedited under hypoxic conditions. Hence, although some of the circulating nitrate and nitrite are excreted in the kidneys they are also able to be recycled back to NO.