Is erythropoietin-induced hypertension a phenomenon due to the intracellular Ca++ mobilisation?

The authors evaluated the ability of rHuEPO (recombinant human erythropoietin) in performing a vasoactive calcium-mediated action. Forty healthy volunteers were evaluated for the muscle blood flow at rest (RBF) and after reactive hyperemia by Xenon 133 clearance. Pre-treatments with several calcium antagonists were used. RESULTS: The i.v. infusion of rHuEPO brought about a reduction of the RBF and MBF (maximal blood flow). This reduction was maintained with nifedipine or verapamil. Gallopamil and ketanserine prevented the reduction of blood flow induced by rHuEPO. CONCLUSIONS. The rHuEPO has a vasoconstrictive action in vivo since gallopamil and ketanserine, drugs able to prevent intracellular mobilisation of the Ca++, can block the rHuEPO induced vasoconstriction. The action exerted by rHuEPO could be due not an increased flow of the Ca++ from the extracellular department but to a mobilisation from Ca++ deposits.