POSTURAL STIMULATION TEST IN PATIENTS WITH ALDOSTERONE-PRODUCING ADENOMAS

OBJECTIVE The purpose of this study was to evaluate the postural stimu lation test before and after surgical treatment in patients with aldos terone-producing adenomas. DESIGN The retrospective study was made on patients with aldosterone producing adenomas. PATIENTS The postural st imulation test was analysed in 60 patients with surgically proven aldo sterone producing adenoma and in 15 healthy volunteers. MEASUREMENTS T he postural stimulation test was based on measurements of plasma aldos terone, cortisol and renin activity (PRA) at 0800 h and at noon after 4 hours ambulation. RESULTS The patients were divided into two groups according to the individual pattern of plasma aldosterone concentratio n following the postural test. Plasma aldosterone concentration decrea sed or did not change after 4 hours of standing in 42 patients (group 1, 70% of total) and increased in 18 patients (group 2, 30% of total). Mean plasma aldosterone was significantly higher in group 1 than in g roup 2 (1325 +/- 164 pmol/l (mean +/- SE) and 538 +/- 53 pmol/l, respe ctively). Mean plasma cortisol concentration after 4 hours of upright posture in both groups remained low (242 +/- 35 vs 401 +/- 65 nmol/l ( group 1) and 317 +/- 46 vs 367 +/- 43 nmol/l (group 2)). Mean PRA in b oth groups was suppressed after 4 hours of upright posture (0.2 +/- 0. 04 vs 0.2 +/- 0.04 pmol/l/s and 0.3 +/- 0.06 vs 0.1 +/- 0.02 pmol/l/s, respectively). CONCLUSION Diverse changes in plasma aldosterone and c ortisol found in response to the postural test may indicate pathogenet ic heterogeneity amongst patients with aldosterone producing adenomas and should be considered during diagnosis of primary aldosteronism.