title: Positive correlation between plasma nitrite and performance during high-intensive exercise but not oxidative stress in healthy men.
abstract: Several studies suggest that exercise is associated with elevated oxidative stress which diminishes NO bioavailability. The aim of the present study was to investigate a potential link between NO synthesis and bioavailability and oxidative stress in the circulation of subjects performing high-intensive endurance exercise. Twenty-two male healthy subjects cycled at 80% of their maximal workload. Cubital venous blood was taken before, during and after exercise, and heparinized plasma was generated. Plasma concentrations of nitrite and nitrate were quantified by GC-MS and of the oxidative stress biomarker 15(S)-8-iso-PGF(2alpha) by GC-MS/MS. pH and pCO(2) fell and HbO(2) increased upon exercise. The duration of the 80% phase (d80) was 740+/-210s. Subjects cycled at 89.2+/-3.3% of their peak oxygen uptake. Plasma concentration of nitrite (P<0.01) and 15(S)-8-iso-PGF(2alpha) (P<0.05) decreased significantly during exercise. At the end of exercise, plasma nitrite concentration correlated positively with d80 and performed work (w80) (each P<0.05). Changes in nitrate concentration also correlated positively with d80 (P<0.05) and w80/kg (P<0.01). These findings provide evidence of a favorable effect of nitrite on high-intensive endurance exercise. The lack of association between 15(S)-8-iso-PGF(2alpha) and NO bioavailability (nitrite concentration) and NO biosynthesis (nitrate concentration) suggest that oxidative stress, notably lipid peroxidation, is not linked to the l-arginine/NO pathway in healthy male subjects being on endurance exercise.
authors.affiliation: Institute of Sport Medicine, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.
authors.forename: Ulrike
authors.initials: U
authors.lastname: Dreissigacker
authors.forename: Marcel
authors.initials: M
authors.lastname: Wendt
authors.forename: Torge
authors.initials: T
authors.lastname: Wittke
authors.forename: Dimitrios
authors.initials: D
authors.lastname: Tsikas
authors.forename: Norbert
authors.initials: N
authors.lastname: Maassen
mesh_terms: D000328:Adult; D015415:Biomarkers / Q000097:blood; D002245:Carbon Dioxide / Q000097:blood / Q000378:metabolism; D015237:Dinoprost / Q000031:analogs & derivatives / Q000097:blood / Q000378:metabolism; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D005240:Feasibility Studies; D008401:Gas Chromatography-Mass Spectrometry; D006262:Health; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D015227:Lipid Peroxidation / Q000502:physiology; D008297:Male; D009566:Nitrates / Q000097:blood* / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis / Q000378:metabolism; D009573:Nitrites / Q000097:blood* / Q000378:metabolism; D018384:Oxidative Stress / Q000502:physiology*; D010100:Oxygen / Q000378:metabolism; D010807:Physical Endurance / Q000502:physiology*; D012016:Reference Values; D013997:Time Factors
chemical_list: D015415:Biomarkers; D006454:Hemoglobins; D009566:Nitrates; D009573:Nitrites; D002245:Carbon Dioxide; C075750:8-epi-prostaglandin F2alpha; D009569:Nitric Oxide; D015237:Dinoprost; D010100:Oxygen