Moreover, physiologic concentrations of 1, 25, dihydroxyvitamin D increases calcium deposition in cultured vascular smooth muscle cells and is associated with reduced expression of PTH related peptide (1-34 PTH) suggesting that amino PTH fragments are not only involved in regulating bone turnover, but also function to prevent dystrophic vascular calcification. Indeed, these observations raise the question of whether carboxy PTH fragments can accelerate vascular calcification.