Aldosterone receptors in different types of primary hyperaldosteronism

The number of mineralocorticoid-binding sites on mononuclear leukocytes and plasma aldosterone (aldo) concentrations were measured in patients with different types of primary hyperaldosteronism. Patients with unilateral adenoma and patients with bilateral adrenal hyperplasia had a significantly lower (P less than 0.001) mean number of binding sites for aldo [144 +/- 36 (+/- SD; n = 6) and 140 +/- 28 sites/cell (n = 4), respectively] compared with normal subjects (292 +/- 110 sites/cell; n = 25). In four patients with dexamethasone-suppressible hyperaldosteronism, mineralocorticoid-binding sites in mononuclear leukocytes were normal (291 +/- 108 sites/cell). In all patients undergoing surgery for unilateral adenoma, the receptors normalized 3 months after the operation. In two patients the reduction in receptors persisted for a short time after surgery even though the plasma aldo level had already normalized. We conclude that mineralocorticoid excess produces down-regulation of mineralocorticoid receptors, which, in turn, might contribute to the genesis of the aldo escape phenomenon.