Atrial natriuretic factor in essential hypertension and adrenal disorders

Patients with untreated essential hypertension had significantly higher plasma atrial natriuretic factor (ANF) levels (92.9 ± 12.9 pg/ml, mean ± SE) than those of age-matched controls (37.8 ± 6.0 pg/ml; p < 0.01). Plasma ANF levels in essential hypertensive patients showed a significant positive correlation with mean arterial pressure (MAP; r=0.46, p < 0.05) and an inverse correlation with plasma renin activity (PRA; r=-0.43, p < 0.05). Plasma ANF levels after medication showed significant correlation with the decrease hi MAP (r=0.565, p < 0.05). Patients with primary aldosteronism had significantly higher plasma ANF levels (122.4 ± 30.2 pg/ml, n=8) than those of controls (p < 0.05). The levels returned to normal after extirpation of adrenal tumors. The response of plasma ANF levels in patients with primary aldosteronism to volume expansion with infusion of 2 L of physiological saline in 2 hours was greater than hi controls. Such exaggerated response disappeared after surgical treatment. Infusion of angiotensin II (Ang II; 20 ng/kg/min) or norepinephrine (200 ng/kg/min) for 30 minutes to normal volunteers (n=5) resulted hi a rise hi MAP (24.9 ± 3.3 and 15.8 ± 4.4 mm Hg, respectively) and a twofold increase in plasma ANF level. Infusion of the Ang II antagonist [Sarl, Der, Ang II (600 ng/kg/min) for 30 minutes, resulted hi a rise hi MAP (18.8 ± 2.1 mm Hg) and more than a twofold increase ui plasma ANF level in patients with essential hypertension (n=6). The increase in the plasma ANF level by the agonistic pressor action of the Ang II antagonist significantly correlated with the increase in MAP (r=0.760, p <; 0.05). These results suggest that the plasma ANF level is one of the important clinical parameters for evaluating the hemodynamic state hi essential hypertension, primary aldosteronism, and other adrenal disorders.