抄録
Twenty-four patients with essential hypertension were classified as salt-sensitive (SS) or non-salt-sensitive (NSS) depending on the changes in mean blood pressure (MBP) when salt intake was increased from 2 g (low-sodium) to 15 g (high-sodium). Although the plasma immunoreactive endothelin-1 (irET-1) levels remained unchanged, fractional excretion of irET-1 (FEET) levels elevated on a high-sodium diet in both groups. Positive correlation was observed between elevation of FEET and fractional excretion of Na (FENa) with a high sodium diet (r=0.53, p<0.05). FEET level on a high-sodium diet were significantly smaller in SS than in NSS group (p<0.05). In addition, FEET was inversely correlated with MBP on high-sodium diet (r=-0.47, p<0.05). The decrements of plasma renin activity was significantly smaller in the SS than in the NSS group (p<0.01). These findings indicate that a large part of the urinary ET is of renal origin, increasing sodium excretion, and that the greater rise in blood pressure in SS patients with sodium loading is attributed to greater sodium retention due to an attenuated secretion of renal ET in addition to a low response of renin.
