Figure 5

Vitamin D₃ treatment increases kidney Ca²⁺ levels in Npt2a^−/− mice. Measurements of P_i and Ca²⁺ levels were carried out in bone and kidney tissues of WT and Npt2a^−/− mice following 4 days of treatment with either a vehicle or vitamin D₃ (n = 6 per genotype). (a & b) There was no difference in the levels of P_i and Ca²⁺ in bone of either genotype in response to vehicle or vitamin D₃ treatment. (c) Kidney P_i levels were not significantly different between genotypes or treatment. (d) The kidney Ca²⁺ levels were significantly greater in response to vehicle treatment in Npt2a^−/− compared to WT mice. Vitamin D₃ treatment was not associated with altered kidney Ca²⁺ levels in WT mice; however, resulted in the highest kidney Ca²⁺ levels in Npt2a^−/− mice. Male mice were used in these studies. In addition to single data summary data are shown and are expressed as mean ± SEM and were analyzed by two-way ANOVA followed by Tukey’s multiple comparisons test. *P < 0.05 vs WT same treatment, ^§P < 0.05 vs vehicle same genotype.