Hypertension corrected and aldosterone responsiveness to renin-angiotensin restored by long-term dexamethasone in glucocorticoid-suppressible hyperaldosteronism.

Two males with glucocorticoid-suppressible hyperaldosteronism had hyperaldosteronism, hypertension and hypokalaemia corrected by continuous administration of physiological doses of dexamethasone for more than a year. During long-term dexamethasone treatment: (a) Plasma renin activity increased from subnormal to high normal levels, with normal posture-mediated increases; (b) Plasma aldosterone became responsive to angiotensin infusion, a new observation; (c) A fall in plasma aldosterone between 0800 h (recumbent) and 1000 h (upright) was replaced by a rise; (d) Plasma aldosterone became suppressible with salt loading. These findings are consistent with a shift to more normal control of aldosterone by renin-angiotensin, once abnormal responsiveness to ACTH has been nullified.