TEI-9648, a Vitamin D 3 Lactone analogue, is a potent and specific vitamin D receptor (VDR) antagonist. TEI-9648 inhibits VDR/VDRE-mediated genomic actions of 1α,25(OH) 2 D 3. TEI-9648 also inhibits HL-60 cell differentiation induced by of 1α,25(OH) 2 D 3. TEI-9648 has the potential for bone metabolism research. In Vitro TEI-9648 (10-1000 nM) dose-dependently blocks the reciprocal changes of CD11b and CD71 expression associated with HL-60 cell differentiation induced by 1α,25(OH) 2 D 3. TEI-9648 has consistently weaker suppressive effect than TEI-9647. TEI-9648 can not induce cell differentiation even after treatment at 1 μM in HL-60 cell. TEI-9648 alone can not induce activation of NBT-reducing activity or α-NB esterase activity. In contrast, TEI-9648 markedly suppresses the up-regulation induced by 1α,25(OH) 2 D 3 (0.1 nM) in HL-60 cells. MCE has not independently confirmed the accuracy of these methods. They are for reference only. Form:Solid