Changes in Urinary Excretion of Epinephrine, Norepinephrine and Dopamine after Gravitional Acceleration Training

ABSTRACT

Urinary excretion of catecholamines (epinephrine, norepinephrine and dopamine) was determined in student pilots during high gravitational acceleration training. A total of 20 student pilots were exposed to +6GZ for 30 seconds using human centrifuge without anti-G suit and urine samples were collected before and after +GZ load. Each urine sample was adjusted to pH 2 with hydrochloric acid and stored at -20degreeC. Urine samples were derivatized with fluorescence using Toyopak SP cartridge and concentration of urinary catecholamines was determined by high-performance liquid chromatography (HPLC) with fluorescence detection. The amount of urinary excretion of catecholamines after exposure to +6GZ was significantly increased in comparison with pre-exposure level (epinephrine, 3.02+/-1.66 to 7.62+/-3.97; norepinephrine, 1.10+/-0.36 to 2.03+/-1.09; dopamine, 3.49+/-1.76 to 5.33+/-3.21 ng/100 mg creatinine). But, there was no difference in catecholamine excretion pattern between passed trainees and failed ones who experienced G-induced loss of consciousness (G-LOC). These data suggest that high +GZ stress was a powerful physical and mental stimuli to all student pilots and resulted in increased excretion of catecholamines. And the cartridge derivatization method was very useful in catecholamine measurement.