Relations between the renin-angiotensin-aldosterone system and urinary elimination of sodium: study of healthy subjects in clinostatism and on a sodium-free diet

In 94 normotensive subjects and free sodium diet, the relationship between SPRA and the 2-hour urinary sodium excretion was significantly better fitted by an hyperbolic function (p less than 0,001); r = 0,53) than a linear one (p less than 0,001; r = -0,31) between SPRA and the 24-hour urinary sodium excretion. (SPRA = Supine Plasma Renin Activity).