Plasma noradrenaline concentration in hypertensive and normotensive forty-year-old individuals: Relationship to plasma renin concentration

Abstract

Forty-year-old individuals with labile and with mild sustained essential hypertension, identified during a survey of a population born in 1936, were investigated. None had ever received antihypertensive treatment. In 33 individuals (26 M [male], 7 F [female]) with diastolic blood pressure (DBP) .gtoreq. 95 mmHg at the very 1st examination and in 31 (14 M, 17 F) randomly selected normotensive controls plasma noradrenaline [norepinephrine, NA] concentration (PNAC) was measured at supine rest. In 22 patients (16 M, 6 F), with sustained diastolic hypertension (DBP .gtoreq. 95 mmHg on at least 3 different occasions) and in 24 (14 M, 10 F) normotensive controls PNAC and plasma renin concentration (PRC) were measured supine at rest and again 2 h after furosemide and ambulation. Basal and acutely stimulated values for PNAC and PRC were identical in hypertensive and normotensive individuals. A close correlation between PNAC and PRC after acute stimulation (r [correlation coefficient] = 0.77, P < 0.001) as well as between the absolute changes from resting to acutely stimulated values (r = 0.72, P < 0.001) were found in the hypertensive individuals. Sympathetic nerve activity, as defined from measurements of plasma NA concentration, apparently is similar in young patients with mild hypertension and in normotensive controls. The discrepancies found in the literature might be related to a lack of comparability between hypertensive and normotensive individuals studied, as far as the source of study populations is concerned.