26- and 27-Methyl groups of 2-substituted, 19-nor-1α,25-dihydroxylated vitamin D compounds are essential for calcium mobilization in vivo
作者:Pawel Grzywacz、Lori A. Plum、Margaret Clagett-Dame、Hector F. DeLuca
DOI:10.1016/j.bioorg.2013.01.001
日期:2013.4
Twelve new analogs of 19-nor-1 alpha,25-dihydroxyvitamin D-3 6-17, were prepared by a multi-step procedure from known alcohols 18 and 19. We have examined the influence of removing two methyl groups located at C-25, as well as the 25-hydroxy group, on the biological in vitro and in vivo biological activity. Surprisingly, removal of the 26- and 27-methyl groups from either the 2 alpha-methyl or 2-methylene-19-nor-1 alpha,25-dihydroxyvitamin D-3 reduced vitamin D receptor binding, HL-60 differentiation, and 25-hydroxylase transcription in vitro only slightly to moderately (compounds 6-13). However, these compounds were devoid of in vivo bone mobilization activity and had markedly reduced activity on intestinal calcium transport. The analogs 14-17 with a 2 beta-methyl substitution had little or no activity in vitro and in vivo as expected from previous work. (C) 2013 Elsevier Inc. All rights reserved.