1. Pronounced hypoaldosteronism was found in five young women with low-renin hypertension and characteristic features of the mineralocorticoid hypertensive syndrome.
2. There was no overproduction of the mineralocorticoids 11-deoxycorticosterone and 18-OH-11-deoxycorticosterone.
3. Dexamethasone restored blood pressure to normal, decreased body weight, increased plasma potassium, and increased plasma renin activity and aldosterone excretion in all patients.
4. The data suggest overproduction of an unknown adrenocorticotrophic hormone-dependent mineralocorticoid maintaining hypertension in these patients.