Aldosterone regulation in primary aldosteronism: differences between adenoma and bilateral hyperplasia.

The diurnal patterns of plasma aldosterone, plasma renin activity (PRA), cortisol and adrenocorticotrophic hormone (ACTH) in the supine and in the upright position have been studied in 14 patients with primary aldosteronism, 5 with adenoma and 9 with bilateral hyperplasia. Blood samples were drawn at intervals from 6 hr to 30 min. Supine patients with an adenoma showed marked diurnal variations of aldosterone, with maximal values at 08.00 hr and minimal values at 18.00 hr and secretory spurts beginning after 02.00 hr. Plasma cortisol paralleled aldosterone, and ACTH seemed to anticipate aldosterone and cortisol variations; PRA remained unchanged. In patients with hyperplasia, aldosterone was significantly lower than in the adenoma group at 08.00 hr, and its decline during the day was less marked; fluctuations rather than secretory episodes were seen. After patients assumed the upright posture, aldosterone remained unchanged or decreased in patients with adenoma, whereas it significantl...