Subgroups of Primary Hypertension Divided by Exaggerated Natriuresis

• Published in: Nihon Jinzo Gakkai shi Vol. 22; no. 9; pp. 1165 - 1172
• Main Authors: Ito, Keiichi, Ikeda, Masao, Kojima, Shunichi, Natsume, Takashi, Satani, Makoto, Sakaguchi, Akira, Tsuchiya, Masayuki, Nakazawa, Masahiro, Kimura, Genjiro
• Format: Journal Article
• Language: Japanese
• Published: Japan Japanese Society of Nephrology 1980
• Subjects: exaggerated natriuresis; Humans; Hypertension - physiopathology; Natriuresis
• ISSN: 0385-2385; 1884-0728
• DOI: 10.14842/jpnjnephrol1959.22.1165

The natriuretic response to intravenous infusion 1.5 litre isotonic saline over 90 min. was studied in 29 subjects under normal salt diet (8-10gm./day) and repeated in some patients under low salt diet (2-3gm./day). Twenty-nine subjects consisted of 18 patients with primary hypertension, 4 patients with renovascular hypertension, 2 patients with primary aldosteronism, and 5 normotensive subjects. Fractional excretion of sodium after 2 hr. of saline load was significantly higher in hypertensive patients than in normotensive subjects. Of these hypertensive patients, patients with primary aldosteronism showed the greatest natriuresis. The degree of the exaggerated natriuresis observed in patients with primary hypertension was dependent upon the dietary sodium intake of each patient. However, of 18 patients with primary hypertension, 6 patients showed a greater hypernatriuresis which deviated from the positive relation between natriuresis following saline load and dietary sodium intake. Therefore, it was possible to divide the patients with primary hypertension into two group (group A and B) depending on degree of the exaggerated natriuresis : i. e., group A demonstrated a significant greater natriuretic response to saline infusion than did group B. Restriction of sodium intake obscured the greater hypernatriuresis observed in group A. There was no significant difference in mean arterial blood pressure, age, GFR, RPF, FF, between group A and B. However, urinary potassium and phosphorus excretion increased significantly following saline load in only group A. Group A had a tendency of low renin, but they were not identical comple-tely with low renin essential hypertension, The greater hypernatriuresis to saline load observed in group A is similar to the hypernatriuresis which have been obtained in escape phase of normal subjects administered aldosterone. Therefore, it is postulated from these results that group A may be compensa-ting for a impaired sodium excretion with accelating of a natriuretic factor.