Yoshizumi M, Nakaya Y, Hibino T, Nomura M, Minakuchi K, Kitagawa T, Katoh I, Ohuchi T, Oka M
Department of Cardiovascular Surgery, School of Medicine, University of Tokushima, Japan.
Life Sci. 1992;51(3):227-34. doi: 10.1016/0024-3205(92)90079-5.
To elucidate whether sulfoconjugated catecholamines in plasma, especially dopamine, serve as a source of free catecholamines, we examined the change in afterload on the deconjugating activity of catecholamines in isolated Langendorff perfused rat hearts. Dopamine-sulfate was administered under ordinary or high-work-load conditions. Free dopamine in the effluent was increased by the high-work-load of the hearts, whereas conjugated dopamine showed an apparent decrease. These results indicate the possibility that deconjugation of sulfoconjugated catecholamines is accelerated by a high-work-load. To obtain further evidence in humans, we also examined the changes in the plasma levels of free and sulfoconjugated catecholamines in healthy volunteers before and after marathon running. Free dopamine increased 1.99-fold from the baseline value after exercise, whereas conjugated dopamine decreased by 12%. Similarly, the plasma levels of free noradrenaline and adrenaline increased after exercise to 2.45- and 1.51-fold their respective baseline values, while conjugated noradrenaline and adrenaline both decreased. These clinical results, as well as those of the experimental studies, suggest that the increase in plasma free catecholamines after exercise is due not only to increased release from the sympathoadrenal system but also to accelerated conversion from sulfoconjugated catecholamines in the plasma.
为了阐明血浆中硫酸化儿茶酚胺，尤其是多巴胺，是否作为游离儿茶酚胺的来源，我们研究了在离体Langendorff灌注大鼠心脏中，后负荷对儿茶酚胺去结合活性的影响。在普通或高工作负荷条件下给予硫酸多巴胺。心脏的高工作负荷使流出液中的游离多巴胺增加，而结合多巴胺明显减少。这些结果表明，高工作负荷可能会加速硫酸化儿茶酚胺的去结合。为了在人体中获得进一步的证据，我们还检测了健康志愿者马拉松跑步前后血浆中游离和硫酸化儿茶酚胺水平的变化。运动后，游离多巴胺较基线值增加了1.99倍，而结合多巴胺减少了12%。同样，运动后血浆中游离去甲肾上腺素和肾上腺素水平分别增加至各自基线值的2.45倍和1.51倍，而结合去甲肾上腺素和肾上腺素均减少。这些临床结果以及实验研究结果表明，运动后血浆游离儿茶酚胺的增加不仅归因于交感肾上腺系统释放增加，还归因于血浆中硫酸化儿茶酚胺转化加速。
