Fig. 1From: Vitamin D3 metabolite ratio as an indicator of vitamin D status and its association with diabetes complicationsThe Vitamin D3 pathway. In the skin, 7-dehydrocholesterol is converted to previtamin D3 and then to vitamin D3. This is transported to the liver, converted to 25 hydroxyvitamin D (25(OH)D3) and then transported to the kidney. In the kidney, 25(OH)D3 undergoes conversion to the active 1,25 (OH)2D3, and 24,25(OH)2D3Back to article page