Abnormalities of the vitamin D receptor in uraemia

The 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃) receptor mediates many of the actions of 1,25(OH)₂D₃ in cells of target tissues. Abnormalities in vitamin D receptor concentration and regulation exist in tissues of subjects with chronic renal failure and end-stage renal disease. There is evidence that inhibitors of vitamin D receptor-1,25(OH)₂D₃ binding and 1,25(OH)₂D₃ action are present in dialysates and sera of individuals with end-stage renal disease. The biological significance of decreased vitamin D receptor number and altered vitamin D receptor regulation in uraemia is unclear at present as responses to 1,25(OH)₂D₃ in uraemia have not been systematically compared with responses in normal subjects.