Erythropoietin-induced hypertension in rat is not mediated by alterations of plasma endothelin, vasopressin, or atrial natriuretic peptide levels.

Abstract

Regular administration of recombinant erythropoietin (EPO) in patients with chronic renal failure (CRF) is frequently complicated by a rise in arterial blood pressure. Clinical studies intended to discern the possible role of endothelin (ET) in the pathogenesis of EPO-induced hypertension have produced contradictory results. Given the limitations of the clinical studies, this placebo-controlled study was carried out in CRF (5/6 nephrectomized) rats treated with either EPO, 150 U/kg intraperitoneally, or the vehicle alone twice weekly for 6 wk. Plasma ET was measured at baseline, and weeks 2, 4, and 6. In addition, plasma arginine vasopressin (AVP) and atrial natriuretic peptide (ANP) were determined at the conclusion of the study period. As expected, blood pressure rose markedly after 1 wk of EPO therapy as compared with the placebo therapy. However, there was no significant difference in plasma ET levels between the EPO- and placebo-treated groups during the study period. Likewise, EPO therapy had no effect on plasma ANP level but depressed plasma AVP concentration. Thus, this placebo-controlled animal study revealed that EPO therapy markedly raised arterial blood pressure but had no effect on plasma ET in the CRF rats. This observation suggests that EPO-induced hypertension in this model is not mediated by an increased circulating ET level. However, the possible effect, if any, of EPO on local vascular tissue ET level is uncertain and awaits further investigation.