We measured brachial BP ( bBP ) , central BP ( cBP ) , GFR , urinary output ( OU ) , free water clearance ( CH2O ) , fractional excretion of sodium ( FENa ) , urinary excretion of albumin ( UAER and UACR ) , AQP2 ( u-AQP2 ) and ENaC ( u-ENaC ) and plasma concentrations of vasoactive hormones : renin , angiotensin II , aldosterone , arginine vasopressin , endothelin-1 and brain natriuretic peptide .