This study describes the effects of [des-Aspartyl(1)]-
angiotensin II ([des-Asp]-AII) on blood pressure and
aldosterone production in patients with primary
aldosteronism due to
aldosterone-producing adrenal
adenoma (APA) and idiopathic adrenal
hyperplasia (IHA), and in normotensive control subjects. 10 patients with primary
aldosteronism, 7 with APA and 3 with IHA, and 6 normotensive control subjects were placed on a constant 150-meq
sodium diet for 4 days. [des-Asp]-AII was infused for 30 min at 6, 12, and 18 pmol/kg per min. Three groups of patients were identified on the basis of
aldosterone response to [des-Asp]-AII. Group I, composed of normotensive control subjects, showed incremental increases in plasma
aldosterone concentration from 6+/-1 to 14+/-3 ng/100 ml (P < 0.01) with [des-Asp]-AII infusion. Group II, composed of patients with primary
aldosteronism, showed incremental increases in plasma
aldosterone concentration from 33+/-8 to 65+/-13 ng/100 ml (P < 0.05) with 12 pmol/kg per min of [des-Asp]-AII. Group III, also composed of patients with primary
aldosteronism, showed no increase of plasma
aldosterone concentration with [des-Asp]-AII. Groups I and II showed similar percentage increases in plasma
aldosterone concentration (P = NS). Group III showed significantly lower
aldosterone responses than group I (P < 0.01). Group II included all patients with IHA and two patients with APA. Group III included only patients with APA. The blood pressure responses to [des-Asp]-AII of subjects in group I did not differ significantly from those of groups II or III.Thus, patients with IHA and a subgroup of patients with APA showed responsiveness to [des-Asp]-AII which was limited to adrenal cortical stimulation of
aldosterone biosynthesis. This suggests that adrenal responsiveness to
angiotensin is a major control mechanism in some forms of primary
aldosteronism. The differential adrenal responsiveness to [des-Asp]-AII in patients with APA indicates either that there are two distinct subpopulations of APA, or that alteration in
tumor response to
angiotensin occurs during the natural progression of the disease history.