NSCs were cultured in the presence or absence of 1,25(OH)2D3 (10−6 M) for 5 days and mRNA expression of neurotrophic factors was determined by quantitative RT-PCR. The experiments were performed in triplicate, and the relative expression level of each neurotrophic factor was calculated by the ratio of values in wells with and without added 1,25(OH)2D3. Data represent the mean ± SEM of triplicate samples analyzed. **P < 0.01, ***P < 0.001, comparison between 1,25(OH)2D3-treated and untreated cells. One representative of three experiments is shown.