Transcriptional and Post-Transcriptional Regulation of PTH Gene Expression by Vitamin D, Calcium and Phosphate

1,25(OH)₂D₃ the biologically active metabolite of vitamin D is synthesized in the renal proximal tubules from the hepatic metabolite 25 (OH)D. Lack of 1,25(OH)₂D₃ is relevant to the pathogenesis of secondary hyperparathyroidism, and 1,25(OH)₂D₃ itself is used effectively in the management of renal failure patients to prevent secondary hyperparathyroidism. The scientific basis of this therapy is the finding that 1,25(OH)₂D₃ potently decreases PTH gene transcription both in vitro and in vivo.