1,25-Dihydroxyvitamin D3 does not up-regulate vitamin D receptor messenger ribonucleic acid levels in hypophosphatemic mice

Shigeo Nakajima, Kanji Yamaoka, Shintaro Okada, J. Wesley Pike, Yoshiki Seino, Mark R. Haussler

Research output: Contribution to journalArticle

9 Scopus citations

Abstract

The effect of 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) administration on duodenal vitamin D receptor (VDR) mRNA levels in hypophosphatemic (Hyp) mice, a murine homologue of human X-linked hypophosphatemic rickets, was examined. Basal levels of VDR mRNA in Hyp mice were similar to those of normal littermates and, in normal mice, VDR mRNA levels were up-regulated 1.8-2.7-fold after injection of 1 μg/kg 1,25(OH)2D3. In contrast, no significant change in VDR mRNA was observed in Hyp mice treated with 1,25(OH)2D3. To determine the effect of phosphate repletion on VDR mRNA levels, high-phosphate diet was fed to Hyp mice. Although plasma phosphorus concentration was restored to normal, up-regulation of VDR mRNA was not recovered with phosphate supplementation. These results indicate that the vitamin D-resistance in Hyp mice is not caused by hypophosphatemia, per se, and may result from a fundamental molecular defect in vitamin D action at the intestine which could be related to ineffective up-regulation of VDR mRNA by 1,25(OH)2D3.

Original languageEnglish (US)
Pages (from-to)201-213
Number of pages13
JournalBone and Mineral
Volume19
Issue number3
DOIs
StatePublished - Dec 1992

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Keywords

  • Duodenum
  • Hyp mouse
  • Vitamin D hormone
  • Vitamin D receptor autoregulation
  • X-linked hypophosphatemic rickets

ASJC Scopus subject areas

  • Surgery
  • Biochemistry
  • Endocrinology

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