Are plasma ANP levels elevated in patients with primary aldosteronism compared to those with essential hypertension and healthy subjects?
Plasma ANP levels are elevated in primary aldosteronism, likely due to volume expansion, but remain normal in uncomplicated essential hypertension.
Plasma levels of atrial natriuretic peptide (ANP) were measured in 9 patients with primary aldosteronism and 41 patients with essential hypertension (class I or II by WHO classification) using a specific and sensitive RIA. The mean plasma ANP concentration in patients with primary aldosteronism (mean +/- SEM, 67.1 +/- 10.8 pg/ml; n = 9) was significantly higher than that in healthy normotensive subjects (37.9 +/- 1.4 pg/ml; n = 108) or patients with essential hypertension (38.5 +/- 2.8 pg/ml; n = 41). During treatment with spironolactone, plasma levels of ANP declined in 6 of the 7 patients with primary aldosteronism, but no change occurred in the remaining patient who had cardiac enlargement of unknown etiology. The mean plasma ANP concentration in patients with essential hypertension, on the other hand, was not significantly different from that in normal subjects. These results indicate that plasma ANP levels are elevated in patients with primary aldosteronism, probably due to volume expansion, whereas no abnormality in ANP secretion exists in patients with uncomplicated essential hypertension.
YAMAJI et al. (Wed,) studied this question.