Figure 1. Longitudinal analysis of 25-OH vitamin D in mice given differential vitamin D3 supplementation. Six-month-old C57BL/6J male mice were given 1000 IU vitamin D3/kg chow (STD, black line, n=6), 125 IU (LOW, dark gray line, n=6), or were changed from 125 IU to 1000 IU after 2 months (light gray line, n=8) (A). After 12 months serum calcium (B), 1,25 (OH)2 vitamin D (C), and intact PTH (D), were assessed in STD and LOW mice using calorimetric assays or ELISA. Intact PTH was not significantly different (ns, p=0.10).