Letter to the Editor Nephron 1992:60:111 Acute Effect of Erythropoietin on Plasma Renin Activity and Aldosterone Levels in End-Stage Renal Disease levels after intra venous application ofrhEPO. r 370 350 330 l 310 Time afte' dosing, min NurolArik Fatih Demirkan Belkis Erbas Turgay Arinsoy Cem Sungur Una! Yasavul Cretin Turgan Zebra Koray $ali Qaglar Departments of Nephrology and Nuclear Medicine. Hacettepe University, School of Medicine, Ankara, Turkey Dear Sir, Approximately one third of the patients treated with recombinant human erythro poietin (rhEPO) will experience either an ag gravation of preexisting hypertension or will develop de novo hypertension [1], But the underlying mechanism is unclear and various causes such as the increased blood viscosity and total red cell mass inducing an increase in peripheral resistance [2] and the reversal of compensatory vasodilatation induced by re nal anemia [3] have been proposed by several studies before. Besides, some investigators have suggested that rhEPO itself has some effect on renin-angiotensin-aldosterone axis. So, it has been proposed that the alterations in this axis may contribute to the changes in blood pressure during rhEPO treatment [4,5]. In order to clarify the acute effect of rhEPO on plasma renin activity (PRA) and aldoste rone secretion, we studied PRA and aldoste rone levels after rhEPO injection in 9 prcdial- ysis uremic patients. We included 9 patients with chronic renal failure, untreated by dialysis previously. The patients had never taken rhEPO, antihyper tensives, and the drugs affecting the renin-an giotensin axis and aldosterone secretion such as aldosterone antagonists and angiotensin converting enzyme inhibitors. Patients were maintained at bedrest in supine position for 6 h prior to rhEPO injection and they kept their supine position throughout the test. Af ter the baseline sampling at 8.00 a.m. rhEPO was given intravenously at a dose of 50 U/kg. Blood samples for analysis were taken at 15, 30 and 60 min after injection and blood pres sures were recorded simultaneously. Blood pressure readings did not vary sig nificantly during the study (p > 0.05). Figure I shows that the observed changes in PRA and plasma aldosterone levels after rhEPO injection were not found to be statistically significant (p>0.05). In conclusion, our findings indicate that acute administation of rhEPO does not have any direct effect on PRA and aldosterone secretion in chronic renal failure. References 1 Schaefer MF. Walter HH. Massry SG: Treat ment of renal anemia with recombinant human erythropoietin. Am J Nephrol 1989:9:353-362. 2 Neff MS, Kim KE, PersofTM, Onesti G. Swartz C: Hemodynamics of uremic anemia. Circula tion 1971:43:876-883. 3 Coleman TG: Hemodynamics of uremic ane mia. Circulation 1972:45:510-511. 4 Bucmi M, Aloisi C. Morabito N, Privitera M, Allegra A, Macri I, Squadrito F, Frisina N: Effects of erythopoietin on aldosterone secre tion in hypertensive patients: study in vivo and in vitro (abstract). 13th Scientific Meeting of the International Society of Hypertension, Mon treal 1990, p 308. 5 Lederla RM, Saul F, Klaus D, Schwarze D: Influence of erythropoietin on hemodynamics, left ventricular performance and neurohumoral factors in endstage renal failure (abstract). 13th Scientific Meeting of the International Society of Hypertension. Montreal 1990, p 224. Dr. Nurol Arik Haccttepc Hastancsi Ncfrûloji Bölümü TR-06100 Haccttepe-Ankara (Turkey) ® 1992 S. Karger AG, Basel 0028-2766/92/ 0601-011IS2.75/0