Changes in tissue Na+ content after renal transplantation (RT) and comparison to age- and sex-matched control subjects. Individual muscle (a) and skin (b) tissue Na+ significantly decreased after renal transplantation (n = 31). (c) Mean muscle Na+ content significantly decreased 3 months after transplantation and persisted on this level (red box plots, n = 29 [3 months], n = 31 [6 months]). Six months after surgery, muscle Na+ of kidney transplant recipients was still significantly higher compared to control subjects (blue box plot, n = 31)). (d) Mean skin Na+ content significantly decreased 3 months after transplantation and persisted on this level (red box plots, n = 29 [3 months], n = 31 [6 months]). Six months after surgery, skin Na+ of kidney transplant recipients was no longer significantly different compared to control subjects (blue box plot, n = 31). ∗∗P < 0.001. ∗P < 0.05. a.u., arbitrary units; MRI, magnetic resonance imaging; n.s. not significantly different.