The synthesis and biological activity of 25-hydroxy-26,27-dimethylvitamin D3 and 1,25-dihydroxy-26,27-dimethylvitamin D3: highly potent novel analogs of vitamin D3

Harpal S. Gill, James M. Londowski, Robert A. Corradino, Alan R. Zinsmeister, Rajiv Kumar

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


We synthesized 25-hydroxy-26,27-dimethylvitamin D3, 9, and 1,25-dihydroxy-26,27-dimethylvitamin D3,14, from chol-5-enic acid-3β-ol and tested their biological activity in vivo and in vitro. 9 was found to be a highly potent vitamin D analog with bioactivity similar to that of 25-hydroxyvitamin D3. 9 bound to rat plasma vitamin D binding protein with approximately one-third the affinity of 25-hydroxyvitamin D3. In a duodenal organ culture system and in a competitive binding assay with chick intestinal 1,25-dihydroxyvitamin D receptor, 9 was significantly more potent than 25-hydroxyvitamin D3. 1,25-Dihydroxy-26,27-dimethylvitamin D3, 14 was also highly active in vivo. At doses of 1000-5000 pmol/rat, its action was more sustained than that of 1,25-dihydroxyvitamin D3.14 bound to vitamin 0 binding protein about 18 times less effectively than 1,25-dihydroxyvitamin D3. 14 bound to the chick intestinal cytosol receptor with an affinity one-half that of 1,25-dihydroxyvitamin D3. In a duodenal organ culture system, 14 was about half as active as 1,25-dihydroxyvitamin D3. Extension of the sterol side chain, at C-26 and C-27, by methylene groups, prolongs the bioactivity of a vitamin D sterol hydroxylated at C-1 and C-25; the corresponding sterol, hydroxylated only at C-25, does not show any alteration of its bioactivity in vivo. These newly synthesized analogs may potentially be of therapeutic use in various mineral disorders.

Original languageEnglish (US)
Pages (from-to)147-160
Number of pages14
JournalJournal of Steroid Biochemistry
Issue number2
StatePublished - Aug 1988

ASJC Scopus subject areas

  • Biochemistry
  • Endocrinology


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