Because of the possibility that aldosterone may contribute to the HBP of patients on dialysis, independent of an effect on sodium excretion (since such patients excrete little urine), this protocol is designed to test this possibility by administering an ARA to patients on chronic dialysis with HBP. A positive result would strongly suggest that there is an effect to lower HBP independent of sodium excretion. Such a result would be indicative of a non-Na mechanism for ARA to lower HBP in dialysis patients, but would also suggest the possibility of ARA acting by a non-Na mechanism in lowering HBP in essential HBP.