Endothelin-1 urinary excretion, but not endothelin-1 plasma concentration,is increased in renovascular hypertension

Animal experiments have shown an increase in prepro-endothelin-1 (prepro-ET -1) mRNA expression in the clipped kidney but none In the aortic and mesent eric arteries in 2-kidney, 1-clip Goldblatt hypertensive rats. The present study was aimed at investigating whether plasma and renal endothelin-1 (ET- 1) systems are differently activated in patients with renovascular hyperten sion (RH). The plasma concentration and urinary excretion of ET-1 were meas ured in 5 patients with RH (before and after successful renal angioplasty), in 7 patients with essential hypertension (EH), and in 8 normotensive cont rol subjects, Immediately before renal angioplasty, plasma samples for ET-1 and plasma renin activity (PRA) measurements were withdrawn from the aorta and both renal veins. Unlike the PRA, the plasma ET-1 concentration did no t significantly differ between the involved and the uninvolved sides. The u rinary ET-1 excretion level (Fig 1) was markedly increased in patients with RH (30 +/- 4 ng/g urinary creatinine (UC) vs 2.5 +/- 0.2 ng/g UC and 2.6 /- 0.5 ng/g UC in control subjects and patients with EH, respectively; P <. 001), whereas the plasma ET-1 concentration wets normal (0.8 +/- 0.2 pg/mL vs 0.65 +/- 0.3 pg/mL and 0.8 +/- 0.2 pg/mL in control subjects and EH, res pectively, not significant). Renal angioplasty was followed in all patients by normalization of blood pressure and PRA. One week after angioplasty, ur inary ET-1 decreased to one fourth of baseline (8.04 +/- 5.23 ng/g UC, P<.0 01 vs values before angioplasty and P<.04 vs control subjects) and normaliz ed 1 month thereafter (3.13 +/- 1.62 ng/g UC, not significant vs control su bjects), whereas plasma ET-1 remained steady The present findings clearly i ndicate that in patients with RH, urinary ET-1 excretion is Increased, wher eas plasma ET-1 concentration remains normal. Successful percutaneous trans luminal renal angioplasty induced a notable reduction in ET-1 urinary excre tion, whereas it did not affect ET-1 plasma concentration.