Quantitative proteomic analysis of urinary exosomes from patients with primary aldosteronism that underwent fludrocortisone suppression test

The sodium chloride cotransporters (NCC) and the epithelial sodium channel (ENaC) have been reported to be the main effectors of aldosterone in Na+ and Cl- reabsorption in the distal nephron and dietary K+ downregulates NCC. The Cl-/HCO3- exchanger pendrin has been revealed as a key role in maintaining extracellular fluid and electrolyte homeostasis by regulating Cl- reabsorption in the aldosterone-sensitive distal nephron working in tandem with ENaC and perhaps NCC. Pendrin-mediated Cl-/HCO3- exchange is stimulated in models of metabolic alkalosis (e.g. aldosterone administration or dietary NaHCO3 intake), and plasma K+ level is thought to negatively influence pendrin. In this study we used high-throughput proteomics and bioinformatics approaches to analyze urinary exosome contents isolated from patients undergoing fludrocortisone suppression test (FST, as a means of confirming or excluding primary aldosteronism [PA]) to examine the actions of administration of aldosterone analogs, NaCl and KCl orally on transmembrane proteins existing in urinary exosomes.