Norepinephrine and calcium responses to altered sodium intake in modulating and non-modulating high-renin hypertension.

Sodium sensitivity in subjects with high-renin hypertension has been associated with non-modulation of cardiovascular and biochemical responses to alteration in sodium intake. Using the percentage suppression of plasma renin activity in response to an increase in dietary sodium intake, high-renin hypertensive subjects were categorized in two groups. In association with the increase in sodium intake, modulators showed greater than 58% suppression of plasma renin activity, and significant reductions in mean arterial pressure, plasma aldosterone, norepinephrine and serum calcium concentration. Non-modulators had no significant change in plasma renin activity, mean arterial blood pressure, plasma aldosterone, norepinephrine or serum calcium concentration. The blood pressure response to an increase in dietary sodium intake may be a composite of responses of the renin-angiotensin-aldosterone axis, the adrenergic nervous system and calcium regulatory system.