Relation of plasma noradrenaline to blood pressure, age, sex and sodium balance in patients with stable essential hypertension and in normotensive subjects.

1. Plasma noradrenaline was measured in 125 patients with stable essential hypertension (WHO I-II) and in 107 normotensive control subjects lying and standing. 2. In normotensive subjects and in patients with essential hypertension no sex-related differences of plasma noradrenaline were found between age-matched groups. 3. Plasma noradrenaline was not related to sodium balance indexed by urinary sodium/creatinine ratio. 4. In patients with essential hypertension plasma noradrenaline increases with age. 5. Mean plasma noradrenaline concentrations are significantly higher in patients with essential hypertension compared with age-matched normotensive subjects both lying and standing. 6. In patients with essential hypertension diastolic blood pressure and heart rate correlated significantly with supine plasma noradrenaline concentrations.