Effect of Haemodialysis on Plasma Dopamine-β-Hydroxylase Activity

• Published in: The Japanese Journal of Nephrology Vol. 20; no. 7; pp. 821 - 826
• Main Authors: Nakamura, Shinya, Takahashi, Kojiro, Katoh, Katsumi, Sawaki, Shinji, Hidaka, Hiroyoshi, Tsutsui, Shuichi, Nomura, Takehiko, Shibata, Masao, Kobayashi
• Format: Journal Article
• Language: Japanese
• Published: Japanese Society of Nephrology 1978
• ISSN: 0385-2385; 1884-0728
• DOI: 10.14842/jpnjnephrol1959.20.821

In order to study the influence of haemodialysis on dopamine-β-hydroxylase (DBH) activity in plasma, we measured plasma DBH, total plasma protein and blood pressure before and after hae-modialysis in fourteen patients with chronic uremias. DBH activity was determined by modified method of Creveling et al. As Co-enzyme A, cystein and other -SH compounds are known to inhibit DBH, the level of endogenous DBH inhibitors in Plasma was also examined by using purified beef adrenal DBH preparation which is free from endogenous inhibitors. The DBH activity per ml of plasma was significantly elevated after haemodialysis. Although plasma total protein also in-creased following the dialysis, DBH activity per mg plasma protein was also higher after the dialysis than that before the dialysis. On the other hand, inhibition of purified DBH by the plasma obtained after haemodialysis was more marked than by the plasma before dialysis, suggesting that endogen-ous DBH inhibitors increased after haemodialysis. These results indicate that absolute DBH activity in plasma obtained after haemodialysis is virtually higher than the estimated activity and elevation of plasma DBH after haemodialysis was neither due to the decrease in endogenous inhibitor nor the increase in the activators. Haemodialysis produced the reduction of systolic and diastolic blood pressure which may be caused by the reduction of extracellular fluid after the dialysis. Several explanations are possible for the increase in plasma DBH activity after haemodialysis as follow; 1) The reduction of extracellular fluid by haemodialysis may stimulate the secretion of DBH from sympathetic nerve terminals and 2) Treatment of the patient with haemodialysis itself stimulate the secretion of DBH, because the treatment itsely is associated with a great stress.