title: Direct vasopressor effect of recombinant human erythropoietin on renal resistance vessels.
abstract: The contractile properties of recombinant human erythropoietin (rHuEPO) on isolated resistance vessels of renal and mesenteric vascular beds were studied in an in vitro model using a small vessel myograph. Under isometric conditions, rHuEPO caused a contraction of this vasculature in a concentration range between 10 U/ml and 200 U/ml. A maximal active wall tension of 1.52 +/- 0.19 mN/mm was obtained under a rHuEPO dose of 200 U/ml. In Ca2+ free solution, the pressor response to high rHuEPO-concentrations was attenuated, and the response to low rHuEPO concentrations was abolished. In the presence of verapamil, phentolamine and saralasin, rHuEPO-induced contractions were not affected significantly. A dose-dependent vasodilatation of mounted vasculature to acetylcholine (ACh) indicated that endothelium remained intact in our preparations. rHuEPO-induced vessel contraction was not abrogated after an enzymatical removal of endothelium by collagenase, confirming that the described contractile responses are endothelial independent. These findings suggest that a direct vasopressor effect of rHuEPO on proximal resistance vessels may contribute to development of hypertension seen in rHuEPO-treated hemodialysis patients.
authors.affiliation: Medical University-Poliklinik, University of Muenster, Germany.
authors.forename: S
authors.initials: S
authors.lastname: Heidenreich
authors.forename: K H
authors.initials: KH
authors.lastname: Rahn
authors.forename: W
authors.initials: W
authors.lastname: Zidek
mesh_terms: D000818:Animals; D004305:Dose-Response Relationship, Drug; D004921:Erythropoietin / Q000009:adverse effects / Q000494:pharmacology*; D006801:Humans; D006973:Hypertension / Q000209:etiology*; D066298:In Vitro Techniques; D007668:Kidney / Q000098:blood supply*; D008297:Male; D009131:Muscle, Smooth, Vascular / Q000187:drug effects*; D051381:Rats; D011921:Rats, Inbred WKY; D011994:Recombinant Proteins / Q000009:adverse effects / Q000494:pharmacology; D014655:Vascular Resistance / Q000187:drug effects*; D014661:Vasoconstriction / Q000187:drug effects*
chemical_list: D011994:Recombinant Proteins; D004921:Erythropoietin