Updated project metadata. The thiazide-sensitive NaCl cotransporter (NCC) is an important pharmacological target in the treatment of hypertension. Human SLC12A3 gene encoding NCC gives rise to three isoforms. Only the isoform 3 has been extensively investigated. The goal of the present study was, therefore, to determine the abundance and localization of NCC1 and NCC2 in comparison to NCC3 in the human kidney as well as their functional properties in physiological and pathological conditions. To this end, the presence of NCC1, NCC2, and NCC3 in the human urinary exosomes was assessed by mass spectrometric analysis.