Divalent ion handling in human kidney donors with increased blood pressure after uninephrectomy

In a prospective study of 21 normal human kidney donors, increases in blood pressure were found in seven of 12 males and in three of nine females within the first year after uninephrectomy. Donors with blood pressure increases were characterized by greater weight and body mass indexes. In addition, urinary phosphate excretion was positively correlated (r = 0.73, p less than 0.001) and tubular reabsorption of phosphate negatively correlated (r = -0.61, p less than 0.01) with blood pressure at the follow-up periods in which increases were observed. All donors experienced an increase in parathyroid hormone levels and urinary cyclic AMP excretion. These changes were accompanied by decreases in urinary calcium and serum phosphate values. Thus, the increase in blood pressure took place in a milieu similar to that of "normocalcemic" hyperparathyroidism. The correlation of phosphate excretion and blood pressure in normal donors suggests an important role for phosphate metabolism in the genesis of hypertension associated with loss of renal mass.