Hypertension and Low Plasma Renin Activity: Presumptive Evidence for Mineralocorticoid Excess

Twenty-three hypertensive patients were divided into two groups by measuring their plasma renin activity (PRA) after 4 hours in an upright posture. Eight patients with low PRA and a low aldosterone secretory rate responded to high-dose spironolactone therapy (400 mg/day for 5 weeks) with normalization of blood pressure and significant weight loss. Fifteen patients, who had normal PRA, did not as a group show any appreciable change in blood pressure or weight from this dose of spironolactone. Reduction of the dose of spironolactone to 100 mg/day resulted in weight gain and return of hypertension in the low-PRA patients. A minimum dose of 200 to 300 mg daily was required to maintain normotension. These studies suggest that an as yet unidentified mineralocorticoid, which could theoretically be responsible for the suppressed PRA and aldosterone secretory rate, may also be instrumental in the development of hypertension in these patients.