Regulation of vitamin D-1α-hydroxylase in a human cortical collecting duct cell line

摘要: Regulation of vitamin D-1α-hydroxylase in a human cortical collecting duct cell line. Background Recent studies have shown that renal expression 25-hydroxyvitamin D 3 -1α-hydroxylase (1α-OHase) is not restricted to proximal tubules. To investigate the significance this expression, we characterized regulation 1α-OHase and activity line (HCD). Methods Expression mRNA protein was assessed by reverse transcription-polymerase chain reaction (RT-PCR) Western blot analyses. Enzyme quantified using as substrate; conversion 1,25-dihydroxyvitamin [1,25(OH) 2 ] 24,25-dihydroxyvitamin then determined thin-layer chromatography. Results HCD cells expressed for 1α-OHase. However, basal 1,25(OH) production lower than observed tubule HKC-8 cells. In both lines, synthesis increased forskolin, parathyroid hormone, low calcium medium. Conversely, treatment with itself decreased activity. This effect more pronounced cells, which also demonstrated significantly higher levels 24-hydroxylase The most striking induction following incubation lipopolysaccharide, coincident CD14 Toll-like receptor 4. Conclusions These results highlight capacity from distal areas nephron. sensitive feedback immune suggest localized role