Implication of renal prostaglandin E in urinary sodium excretion

To investigate the role of renal prostaglandin in the regulation of sodium metabolism, urinary prostaglandin E excretion, an indicator of renal prostaglandin synthesis, urinary sodium excretion, plasma renin activity and urinary aldosterone excretion were measured in 84 normal subjects and 55 patients with essential hypertension on ad lib intake of sodium. The excretion rates of urinary prostaglandin E were 736.8 ± 32.2 ng/day in normal subjects and 394.3 ± 28.7 ng/day in essential hypertensives. The excretion rate was significantly decreased in essential hypertensives (P<0.001). A significant positive correlation was found between urinary sodium excretion and urinary prostaglandin E excretion in normal subjects (r=0.39, P<0.001), and in essential hypertensives (r+0.62, P<0.001). There was no correlation between the renin-angiotensin-aldosterone system and urinary prostaglandin E excretion in normal subjects as well as in essential hypertensives. The present data show that renal prostaglandin might be involved in the renal handling of sodium, and prove the possibility that the decrease of renal prostaglandin synthesis is one of the etiological factors in essential hypertension.