Regulation of type II renal Na+-dependent inorganic phosphate transporters by 1,25-dihydroxyvitamin D3. Identification of a vitamin D-responsive element in the human NAPi-3 gene.

Vitamin D is an important regulator of phosphate homeostasis. The effects of vitamin D on the expression of renal Na+-dependent inorganic phosphate (Pi) transporters (types I and II) were investigated. In vitamin D-deficient rats, the amounts of type II Na+-dependent Pi transporter (NaPi-2) protein and mRNA were decreased in the juxtamedullary kidney cortex, but not in the superficial cortex, compared with control rats.

A vitamin D receptor gene polymorphism in the translation initiation codon: effect on protein activity and relation to bone mineral density in Japanese women.

The effect of a T-C transition polymorphism at the translation initiation codon of the human vitamin D receptor (VDR) gene on the biological function of the encoded protein was investigated. Of 239 Japanese women volunteers subjected to genotype analysis for this polymorphism, 32 (13%) were genotype MM (the M allele is ATG at the putative translation start site), 75 (31%) were genotype mm (the m allele is ACG at the putative translation start site), and 132 (55%) were genotype Mm. The bone mineral density (BMD) in the lumbar spine (L2-L4) was determined for 110 healthy premenopausal women from the volunteers and was shown to be 12.