Satoko Masaoka

Intralymphocytic sodium and free calcium and plasma renin in essential hypertension.

Intraceilular sodium, potassium, and free calcium concentrations were investigated in lymphocytes of 30 patients with essential hypertension and 30 normotensive controls. All subjects were placed on a diet containing 8 to 10 g of sodium chloride per day. Lymphocyte sodium concentration was higher in hypertensive patients than in normotensive controls (19.8 ± 1.8 vs 18.4 ± 1.8 mmol/kg wet weight; p < 0.01), whereas lymphocyte potassium concentration was similar in both groups. Lymphocyte free calcium concentration was also higher in hypertensive patients than in normotensive controls (134.6 ± 13.2 vs 120.2 ± 16.4 nmol/L; p < 0.01). There was a positive correlation between lymphocyte sodium and free calcium concentrations in normotensive controls, in hypertensive patients, and in the subjects combined (r = 0.59, p < 0.01; r = 0.71, p < 0.001; and r = 0.70, p < 0.001, respectively). Lymphocyte potassium concentration was not related to lymphocyte sodium or free calcium concentration in each group. In patients with essential hypertension, intraceilular sodium and free calcium concentrations were negatively correlated with plasma renin activity (r = −0.66, p < 0.001; r = −0.60, p < 0.001, respectively), but they were not related to age, mean blood pressure, serum electrolyte concentration, or plasma norepinephrine concentration. These results suggest that a considerable relationship exists between intraceilular sodium and free calcium in lymphocytes and that, in essential hypertension, the alteration in cellular metabolism of sodium and calcium may be linked to the renin system but not to blood pressure, age, or adrenergic activity.