Fig. 2: Nature and distribution of tissue Na⁺ excess and TonEBP expression upon salt loading.

Panel a bars: empty = WKY, dashed = SHRSP, red = high salt (HS) treatment; all bars show mean ± 95% CI, with individual points (overlay; + and x: female and male automatically detected outliers, respectively; ROUT, Q = 1%); significant differences at predefined comparisons are shown by brackets, on top (two-sided Fisher LSD test; please see also Supplementary Table 1 for sex-specific data and detailed significance). Tissue Na⁺ content increased in all tissues in SHRSP-HS, but in myocardium; with the exception of skeletal muscle, it was consistently paralleled by water accrual. Total Na⁺ + K⁺ concentration in tissues fell in physiological ranges (light blue) and was unaffected by salt loading in either strain, ruling out hypertonic accumulations. Panel b data presented as Delta Ct, median ± 95% CI for all rats; significant differences at two-sided Mann–Whitney test are shown in brackets. Increased TonEBP gene expression followed Na⁺ and water accumulation despite no hypertonicity. For both panels, n = 16–18 animals/group, as per Supplementary Data 1; source data are provided as a Source Data file.