BRAIN AND ATRIAL NATRIURETIC PEPTIDES - A DUAL PEPTIDE SYSTEM OF POTENTIAL IMPORTANCE IN SODIUM-BALANCE AND BLOOD-PRESSURE REGULATION IN PATIENTS WITH ESSENTIAL-HYPERTENSION

Objective: To examine the changes in plasma brain natriuretic peptide (BNP), atrial natriuretic peptide (ANP) and blood pressure in patients with essential hypertension on a low, normal and high sodium intake. Design and methods: Twelve patients with mild-to-moderate essential hy pertension were studied. Plasma, urinary and blood pressure measuremen ts were made with the patients on their usual sodium intake, then on t he fifth day of a low (10 mmol/day) and on the fifth day of a high (35 0 mmol/day) sodium intake, the sequence being allocated randomly. Resu lts: Plasma levels of BNP and ANP increased significantly on the high sodium intake compared with when the patients were on their normal die t. The mean blood pressure on the high sodium intake was not significa ntly different from that with the patients on their normal diet. In co ntrast, plasma BNP and ANP decreased on the low sodium intake, but wer e not significantly different compared with when the patients were on their normal diet. However, there was a significant reduction in the m ean blood pressure on the low sodium intake compared with when the pat ients were on their normal diet. Compared with the normal diet, BNP an d ANP plasma levels showed similar percentage decreases on the low sod ium intake and similar percentage increases on the high sodium intake. Conclusions: These findings suggest that BNP and ANP are released in response to a common stimulus during changes in dietary sodium intake. The changes in plasma BNP and ANP observed with sodium restriction an d sodium loading indicate the potential importance of BNP and ANP as a dual peptide system contributing to the maintenance of sodium balance and blood pressure regulation in patients with essential hypertension , during changes in dietary sodium intake.