Nitricoxide and leukotriene E4 metabolism in skiers and biathlonists with exercise!induced bronchoconstriction in different periods of training season

Abstract

The purpose of the study was to investigate respiratory metabolism of nitric oxide (NO) and urinary LT E4 excretion in exerciseinduced bronchoconstriction (EIB)positive and EIB-negative skiers and biathlonists in different periods of training season. Materials and methods. 92 athletes were examined in precompetitive period and 78 in competitive period of annual training cycle (mean age, 17.5 ± 2.3 years). A control group included 64 healthy non sporty individuals of similar age. EIB was diagnosed using an indirect exercise fieldtest at subfreezing ambient temperature (MasterScreen Pneumo, Jaeger). Pre and postexercise fractional exhaled NO level (FeNO), exjhaled breath condensate (EBC) levels of NO2/NO3 (R&D Systems, USA) and 3-nitrotyrosine (Hycult biotech, Netherlands) were studied. Urinary LT Е4 excretion (Assay Designs, USA) was investigated by ELISA. Results. NO2/NO3 and 3-nitrotyrosine levels in EBC were significantly different in athletes and control group. Skiers and biathlonists demonstrated significantly higher 3-nitrotyrosine level and lower NO2/NO3 level in the competitive period compared to the precompetitive period. EIB-positive athletes had lower baseline FeNO, higher levels of NO metabolites in the EBC. However, significant differences were found only in preexercise NO2 level. Urinary LT E4 was significantly higher in athletes than in controls and did not differ between EIB-positive and EIB-negative athletes. There was a negative relationship between pre and postexercise FEV1 and urinary cysLT E4 level. Conclusion. Repetitive intensive exercise in subfreezing ambient temperature could modify respiratory NO metabolism and cysLT production in athletes.