Fig. 1

1,25(OH)2D3 reduced blood glucose and improved glucose tolerance. Change in fasting blood glucose (FBG) (a) after 4-week intervention with 1,25(OH)2D3. (b–c) Quantification of GHbA1c (b) and INS (c) by ELISA after 4-week intervention with 1,25(OH)2D3. (d–e) Change in the glucose tolerance curve (d) and AUC (e) after 4-week intervention. Each value is expressed as the mean ± SD. **, ***, and **** indicate significant differences at p < 0.01, p < 0.001, and p < 0.0001, respectively.