The incidence of arterial hypertension was evaluated in a partly retrospective study of patients with active acromegaly. Of 37 patients studied, 18 (48%) had hypertension, i.e. a supine blood pressure of > 160/95 mmHg. The type of hypertension was explored further by measuring plasma renin activity and, in some patients plasma aldosterone concentrations before and after stimulation (upright posture or furosemide 80 mg given orally). Urinary 24 h excretion of aldosterone was also determined. About half of the patients with hypertension but also a substantial part of normotensive acromegalics had inappropriately low plasma renin levels both during basal conditions and after stimulation. On the other hand urinary aldosterone excretion was either normal or (in 2 patients) slightly elevated. There was no other evidence of coexistent primary aldosteronism. Our results confirm previous reports of a high frequency of alterations in the renin-angiotensin-aldosterone system in acromegalic patients with growth hormone excess which in some instances may lead to an elevated blood pressure. The biochemical changes have many similarities to low renin essential hypertension. A volume factor may be operating in acromegalic patients with hypertension since in 10 patients treatment with the aldosterone antagonist, spironolactone, with doses between 50–200 mg daily lowered blood pressure to near normal levels. Thus, spironolactone seems to be a worthwhile alternative in the treatment of hypertensive acromegalics.
