Figure 2.

Changes in 1,25(OH)₂D₃ levels and Vdr target gene expression during the 1,25(OH)₂D₃ treatment period in control and 1,25(OH)₂D₃-treated 8-week-old C57BL/6 mice. a, After treatment with repeated doses of 1,25(OH)₂D₃, brain levels (black symbols) of 1,25(OH)₂D₃ rose and fell in unison with those in plasma [gray symbols; from a previous publication (Chow et al., 2013)]; open and filled symbols represent levels in brains of untreated and treated mice, respectively. The lines connect the mean levels. b, Basal mRNA levels of Vdr target genes, Cyp24a1 and Mdr1a, were relatively unaltered in vehicle-treated animals but were increased after treatment. Cyp24a1 levels rose and fell sharply, but Mdr1a mRNA levels were sustained during the dosing period (n = 2–4 for each time point).