Protein synthesis is required for optimal induction of 25-hydroxyvitamin D(3)-24-hydroxylase, osteocalcin, and osteopontin mRNA by 1,25-dihydroxyvitamin D(3).

The regulation of the 25-hydroxyvitamin D(3)-24-hydroxylase gene by 1,25-dihydroxyvitamin D(3) (1,25(OH)(2)D(3)) has been extensively studied. It is well established that two vitamin D response elements in the promoter are responsible for the 1,25(OH)(2)D(3) induction of transcription. Surprisingly, this induction is blocked by the protein synthesis inhibitor, cycloheximide (CHX).