Fig. 7.

Na⁺, K⁺ and urea concentrations in the inner and outer medulla of the kangaroo rat and the Munich-Wistar rat. Na⁺, K⁺ and urea concentrations were determined in three medullary zones: the ISOM, outer 50% of the inner medulla (IM1), and inner 50% of the inner medulla (IM2). The statistical significance of differences between sample means was determined with a two-way, repeated-measures, mixed-model ANOVA, and post hoc Bonferroni adjustments were calculated for each tested effect (zone, species or zone*species). *Significant differences between species in each zone; bars sharing the same letter of the same case are not significantly different from one another.