Fig 2.

Alterations in (a) serum concentration of 24,25(OH)2D, (b) serum concentration of 25(OH)D, (c) ratio of 24,25(OH)2D / 25(OH)D, and (d) serum concentration of cholecalciferol following a single dose of 150,000 IU vitamin D3 (open circles) and daily dose of 5000IU for 28 days (black triangles). The bars represent standard deviations. P values are for comparison of values in daily and single dosing groups at corresponding time points. It can be seen that single high-dose bolus vitamin D induces an increase in the inactivating 24-hydroxylase activity that lasts for around 4 weeks. Reproduced with permission from Ketha et al.²⁶