Nitrite uptake and metabolism and oxidant stress in human erythrocytes.
Am J Physiol Cell Physiol
; 279(6): C1946-54, 2000 Dec.
Article
in En
| MEDLINE
| ID: mdl-11078710
ABSTRACT
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.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Oxidative Stress
/
Erythrocytes
/
Nitrites
Limits:
Humans
Language:
En
Journal:
Am J Physiol Cell Physiol
Journal subject:
FISIOLOGIA
Year:
2000
Document type:
Article
Affiliation country:
United States
Publication country:
EEUU
/
ESTADOS UNIDOS
/
ESTADOS UNIDOS DA AMERICA
/
EUA
/
UNITED STATES
/
UNITED STATES OF AMERICA
/
US
/
USA