Joyce D A, Beilin L J, Vandongen R, Davidson L
Life Sci. 1982 Feb 1;30(5):447-54. doi: 10.1016/0024-3205(82)90461-1.
The responses of plasma free and sulfate-conjugated catecholamines to acute physiological stimulation was examined in normal male subjects. Catecholamines were measured with a sensitive radioenzymatic assay incorporating simultaneous hydrolysis of sulfate conjugates and O-methylation of free norepinephrine and epinephrine. Following 20 minutes recumbency after venepuncture 30 +/- 3% of norepinephrine and 16 +/- 5% of epinephrine was in thr free form. Free catecholamines generally increased during standing, cold immersion and isometric handgrip, but sulfates did not change. Bicycle ergometry markedly increased free catecholamines which rapidly returned to basal levels at the end of exercise. In contrast, sulfated norepinephrine decreased substantially with exercise in all subjects but returned to basal levels 3 minutes after stopping exercise. Epinephrine sulfate varied considerably between subjects but showed a similar, although smaller, fall with exercise. Thus, during physiological stimulation, which caused increases in free norepinephrine and epinephrine levels in plasma, the only consistent change in sulfated catecholamines was a marked fall in norepinephrine sulfate after bicycle exercise. This may indicate saturation of sulfotransferase activity, substrate inhibition or impaired tissue conjugation.
在正常男性受试者中检测了血浆游离儿茶酚胺和硫酸结合儿茶酚胺对急性生理刺激的反应。采用一种灵敏的放射酶分析法测定儿茶酚胺，该方法同时进行硫酸结合物的水解以及游离去甲肾上腺素和肾上腺素的O-甲基化。静脉穿刺后静卧20分钟，30±3%的去甲肾上腺素和16±5%的肾上腺素呈游离形式。在站立、冷浸浴和等长握力试验期间，游离儿茶酚胺通常会增加，但硫酸盐形式的儿茶酚胺没有变化。自行车测力计运动显著增加了游离儿茶酚胺，运动结束时其迅速恢复到基础水平。相比之下，所有受试者运动时硫酸化去甲肾上腺素大幅下降，但运动停止3分钟后恢复到基础水平。硫酸肾上腺素在受试者之间差异很大，但运动时也出现了类似的下降，尽管幅度较小。因此，在导致血浆中游离去甲肾上腺素和肾上腺素水平升高的生理刺激过程中，硫酸结合儿茶酚胺唯一一致的变化是自行车运动后硫酸去甲肾上腺素显著下降。这可能表明硫酸转移酶活性饱和、底物抑制或组织结合受损。
