1α,25-Dihydroxyvitamin D3

• Ultra-high purity
• Used in bone, immunology, and metabolism studies
• Highly cited

1α,25-Dihydroxyvitamin D₃ is the active hormonal form of vitamin D. It inhibits proliferation and induces differentiation of a variety of cells including osteoclasts and HL-60 cells. It is a central regulator of bone and calcium homeostasis. It inhibits proliferation and induces differentiation of a variety of cells including osteoclasts, keratinocytes, HL-60 cells, vascular smooth muscle cells, and bone marrow macrophage precursors. It can activate signal transduction pathways that include hydrolysis of phosphatidylcholine and formation of diacylglycerol in chick myoblasts, and activation of Raf kinase in rat hepatic primary cells and 3T3 fibroblasts. It regulates c-myc proto-oncogene transcription, IL-8 expression, cyclooxygenase induction, and directly activates protein kinase C at physiological concentrations (EC₅₀=16 nM). It up-regulates RANKL level and down-regulates OPG level.