Vitamin D Metabolism Mineral Homeostasis VitD 7-DHCC VitD3 1,25(0H2 24,25(0D2D P Vitamin D Metabolism & Mineral Homeostasis 25-OHD 24,25 (OH)2D 1,25 (OH)2D Ca P PTH VitD3 UVL VitD3 7-DHCC