calcitriol biosynthetic process from calciol vitamin D3 activation biological_process 1alpha,25-dihydroxycholecalciferol biosynthesis calcitriol biosynthesis from calciol bf 1alpha,25-dihydroxyvitamin D3 biosynthesis 1alpha,25(OH)2D3 biosynthesis 2013-05-15T11:46:08Z GO:0036378 Conversion of vitamin D3 from its largely inactive form (calciol, also called cholecalciferol) into a hormonally active form (calcitriol). Conversion requires 25-hydroxylation of calciol in the liver to form calcidiol, and subsequent 1,alpha-hydroxylation of calcidiol in the kidney to form calcitriol. vitamin D biosynthetic process polyol biosynthetic process vitamin D3 metabolic process