The novelty of this study is two-fold: 1) This is the first study that documents the changes in u-NKCC2 in healthy subjects as well in patients with CKD in response to a hypertonic saline load, 2) Measurements of the urinary excretion of NKCC2, AQP2 and ENaCγ in the same study has never been performed previously. Here, SCNN1G is linked to chronic kidney disease.