ENaC protein in urinary exosomes. Exosomes were sedimented from the urine of rats on control and low-Na diets. Each lane was loaded with exosomes from a volume of urine containing 70 µg creatinine. All the α- and γENaC protein that could be detected was in the fully cleaved form. The blots show results from four of eight pairs of animals. Na depletion increased the amount of all three ENaC subunits in exosomes, with mean values of low Na/control of 3.9 ± 0.7 for αENaC, 10.3 ± 3.3 for βENaC, and 4.5 ± 1.1 for γENaC.