Purpose: A natriuretic peptide, brain natriuretic peptide (BNP), has been isolated from porcine hearts. We performed this study to determine if BNP is secreted from the heart and to identify changes, if any, in the plasma BNP concentration in essential hypertension.
Patients and methods: We measured the immunoreactive (ir) BNP concentration at intracardiac sites including the coronary sinus of five patients with heart disease during cardiac catheterization. We examined plasma ir-BNP in 48 hypertensive patients, 15 borderline hypertensive patients, and 25 normotensive subjects.
Results: Plasma ir-BNP in the coronary sinus was greater than at other cardiac sites. The concentration was significantly higher in hypertensive subjects than in borderline hypertensive or normotensive subjects. Hypertensive patients with left ventricular hypertrophy (LVH) established by echocardiography had higher plasma ir-BNP levels than those without LVH. In the hypertensive group, plasma ir-BNP was closely correlated with the LV mass index. In these patients, BNP levels were correlated with mean arterial pressure and inversely correlated with the LV ejection fraction, although these correlations were weak. Reverse-phase high-pressure liquid chromatography showed that the major component of circulating ir-BNP in the hypertensive and normotensive subjects corresponded to authentic human BNP-32.
Conclusions: Human BNP-32 was secreted through the coronary sinus from the heart and may act as a cardiac hormone. Plasma BNP was increased in many of the hypertensive subjects with LVH. The increase in BNP seemed to be related to LVH or the cardiac overload associated with LVH.