Uniformity and diversity of calcium metabolism in hypertension. A conceptual framework.

Calcium metabolism plays an important role in blood pressure homeostasis, although it remains unclear to what extent calcium contributes to or, alternatively, protects against clinical hypertension. To resolve this confusion, hypertensive subgroups were first defined by plasma renin activity, dietary salt sensitivity, sensitivity to calcium channel blockade, and calcium metabolic indices. Using these classification schemes, different patterns of calcium metabolism emerged, each predictive of divergent clinical responses. Patients with low plasma renin activity, low serum ionized calcium levels, and dietary salt sensitivity, such as black and elderly hypertensive patients, may preferentially benefit from calcium supplementation. It is postulated that calcium-regulating hormones and the renin-angiotensin-aldosterone system coordinately monitor dietary mineral intake, and transduce these environmental signals at the cellular level by altering cellular calcium uptake and disposition. Analysis of these hormonal systems is useful diagnostically in defining those patients who would most benefit from non-pharmacologic dietary forms of treatment.