NPPB and chronic kidney disease: In studies of experimental animals, activation of nuclear vitamin D receptors by 1,25(OH)2D3 suppresses the expression and secretion of atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in cardiac myocytes [9-13], while in clinical studies of nondialysis chronic kidney disease patients, individuals treated with 1,25(OH)2D3 for 12 weeks were observed to have improved left ventricular diastolic function as compared with placebo [14].