Charles Cobb
Last active: 1/20/2015

Nitrite uptake and metabolism and oxidant stress in human erythrocytes.

May JM, Qu ZC, Xia L, Cobb CE
Am J Physiol Cell Physiol. 2000 279 (6): C1946-54

PMID: 11078710 · DOI:10.1152/ajpcell.2000.279.6.C1946

Nitric oxide, when released into the bloodstream, is quickly scavenged by Hb in erythrocytes or oxidized to nitrite. Nitrite can also enter erythrocytes and oxidize Hb. The goals of this work were to determine the mechanism of erythrocyte nitrite uptake and whether this uptake causes oxidant stress in these cells. Erythrocytes took up 0.8 mM nitrite with a half-time of 11 min. Nitrite uptake was sensitive to temperature and to the pH and ionic composition of the medium but was not inhibited by the specific anion-exchange inhibitor DIDS. About 25% of nitrite uptake occurred on the sodium-dependent phosphate transporter and the rest as diffusion of nitrous acid or other species across the plasma membrane. Methemoglobin formation increased in proportion to the intracellular nitrite concentration. Nitrite reacted with erythrocyte ascorbate, but ascorbate loading of cells decreased nitrite-induced methemoglobin formation only at high nitrite concentrations. In conclusion, nitrite rapidly enters erythrocytes and reacts with oxyhemoglobin but does not exert a strong oxidant stress on these cells.

MeSH Terms (18)

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid Antioxidants Ascorbic Acid Biological Transport Buffers Dehydroepiandrosterone Sulfate Erythrocytes Free Radicals Humans Methemoglobin Nitric Oxide Nitrites Oxidative Stress Oxyhemoglobins Phosphates Phosphorus Radioisotopes Potassium Sodium

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