Figure 3.

Relative mRNA expression for synthesis and degradation enzymes following single or repeated i.v. administration of 1,25(OH)₂D₃. (A) Renal CYP27B1 mRNA expression is reduced by both single and repeated administration of 60 and 120 pmol 1,25(OH)₂D₃. (B) Renal and (C) ileal CYP24A1 mRNA expression are induced by 1,25(OH)₂D₃ in a dose-dependent manner for single and repeated dosing. Data for vehicle-treated mice (basal level) were averaged and joined by the dashed line (n = 9), whereas data for treated mice are mean ± SEM and joined by a solid line (n = 3–4 different mice). Significant differences between groups were denoted by: ^abasal level versus 2 pmol; ^bbasal level versus 60 pmol; ^cbasal level versus 120 pmol; ^†2 pmol versus 60 pmol; ^‡2 pmol versus 120 pmol; ^#60 pmol versus 120 pmol; *all groups except basal level versus 2 pmol.