Dissociation of specific binding of 25-OH-D3 and resorption in fetal rat bones

A. M. Mellow*, G. V. Stosich, P. H. Stern

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


Specific binding of 25-OH-D3 was measured in cytosol prepared from isolated fetal rat bone cells. Binding was significant after 2 h incubation at 0°C and appeared to be approaching a plateau at 4 h. Binding was half-maximal at 1.7 × 10-10 M 25-OH-D3. 24(R),25-(OH)2D3, which was approximately equipotent with 25-OH-D3 in bone culture, had approximately the same binding activity. 1,25-(OH)2D3, which was 2-3 orders of magnitude more active on resorption, was a much weaker competitor for binding. Vitamin D3, which was inactive in culture, was at least as effective a competitor as 1,25-(OH)2D3. The results suggest that the cytosol site which specifically binds 25-OH-D3 is not the mediator of the bone-resorbing activity.

Original languageEnglish (US)
Pages (from-to)149-158
Number of pages10
JournalMolecular and Cellular Endocrinology
Issue number2
StatePublished - Apr 1978


  • 25-hydroxy vitamin D
  • 25-hydroxyvitamin D receptor
  • bone cells
  • bone cytosol
  • bone resorption
  • vitamin D

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Endocrinology


Dive into the research topics of 'Dissociation of specific binding of 25-OH-D3 and resorption in fetal rat bones'. Together they form a unique fingerprint.

Cite this