Renal prostaglandin E2 and the renin-angiotensin system in hypertensive disorders in man

We studied renal vein concentrations of prostaglandin E2 (PGE2) and activity of the renin-angiotensin system in 9 normotensive young men (NT), 17 hypertensive patients with unilateral renal artery stenosis (URS), and 26 patients with essential hypertension (EH) of whom 12 had low renin essential hypertension (LRH). The PGE2 concentration, plasma renin activity (PRA), and angiotensin II (A II) were measured in the inferior vena cava and were compared with the mean concentration for both renal veins under basal conditions and without pharmacological interference. The renal vein PGE2 concentrations were higher in NT (p less than 0.01) and URS (p less than 0.05) than in LRH. However, there were no significant differences in A II concentrations between the groups, nor were there any correlations to PGE2 concentrations. The positive correlation between PRA and PGE2 (r = 0.29, p less than 0.02) indicates that PGE2 may contribute to the activation of the renin-angiotensin system or that there may be a common mechanism for stimulation of both hormonal systems. Our results are not compatible with the hypothesis that a reduction of PGE2 production is a specific feature of patients with EH.