[Influence of angiotensin on the secretion of aldosterone in idiopathic hyperaldosteronism]

The purpose of study was to investigate the role of angiotensin II in idiopathic primary aldosteronism (IPA) and to evaluate the interest of angiotensin converting enzyme inhibitors (ACEI) in its management. The study concerned 10 hypertensive patients, mean 49 +/- 11 years with idiopathic primary aldosteronism due to bilateral adrenal hyperplasia: plasma renin activity (PRA) less than 1.5 ng/ml/h and plasma aldosterone (PA) greater than 25 ng/100 ml. Adrenal venography and adrenal vein aldosterone levels demonstrated bilateral hyperplasia. PRA and PA were evaluated in recumbent position, then after 4 hours in upright posture. The next day, a "captopril screening test" was performed with PA assays before and three hours after a single oral administration of captopril (1 mg/kg). Upright PRA and PA were slightly increased and acute administration of captopril reduced significantly PA levels in all patients. Blood pressure (BP was unmodified under captopril. These hormonal results demonstrated that adrenal glomerulosa remained sensitive to low concentrations of angiotensin II, and underlined the potential interest of ACEI in the management of IPA. Brown R. demonstrated already an increase of adrenal sensitivity to angiotensin II infusions, and isolated an aldosterone-stimulating factor (ASF). Plasma aldosterone levels were related to increased ASF concentrations but there was no link between PRA and ASF. Carey R. suggested that ASF acts through an increase of the sensitivity of aldosterone production to angiotensin II.(ABSTRACT TRUNCATED AT 250 WORDS)