ATRIAL-NATRIURETIC-FACTOR AND AMBULATORY BLOOD-PRESSURE IN YOUNG MALE-SUBJECTS WITH NORMAL OR BORDERLINE OFFICE BLOOD-PRESSURE

Plasma levels of immuno-reactive atrial natriuretic factor (ANF) and ambulatory blood pressure were studied in 42 male subjects, aged 18 to 31 y, including 24 subjects with normal BP and 18 with borderline essential hypertension. ANF was measured in the morning (9 a.m.-12 a.m.), with the subjects in the supine and in the upright positions. Ambulatory BP was determined in all subjects every 15 minutes, for a whole 24 hour period. A scatter plot of office SBP or DBP versus upright or supine ANF suggested negative relationships (not significant). In contrast, the plasma ANF level was significantly correlated to ambulatory BP, especially to daytime BP (r = -0.52, p < 0.001, between daytime SBP and upright ANF; r = -0.50, p < 0.001, between daytime DBP and upright ANF). The data suggested that ANF is decreased in borderline hypertension, but the decrease can be evidenced only when BP is repeatedly determined to afford reliable data. An inhibition of the atrial release of ANF might be one possible mechanism contributing to the genesis of borderline essential hypertension.