PHYSIOLOGICAL SIGNIFICANCE OF PLASMA SULFOCONJUGATED DOPAMINE IN PATIENTS WITH HYPERTENSION - CLINICAL AND EXPERIMENTAL STUDIES

Sulfoconjugated catecholamines, especially dopamine sulfate, have rece ntly attracted much attention because of the possibility of their conv ersion to active free dopamine by tissue arylsulfatase. In the present study, we have measured the plasma levels of free and sulfoconjugated dopamine in patients with hypertension and have investigated the phys iological significance of sulfoconjugation. Results showed that the pl asma level of dopamine sulfate in patients with essential hypertension was higher than the level in control subjects, and was highest in pat ients with renal hypertension. However, the plasma level of free dopam ine showed no significant difference between patients with hypertensio n and normal subjects. Moreover, after normalization of blood pressure in hypertensive patients with medication, the plasma levels of conjug ated dopamine decreased to almost the control value. In the experiment al study, dopamine sulfate inhibited angiotensin II-induced aldosteron e release from bovine adrenal cortical cells to a similar extent as pr oduced by free dopamine. From these results, we have concluded that pl asma sulfoconjugated dopamine may regulate free dopamine in the plasma of patients with hypertension, and it may have some physiological eff ects on blood pressure regulation.