25-hydroxy Cholesterol contains six deuterium atoms at the 26, 26, 26, 27, 27, and 27 positions. It is intended for use as an internal standard for the quantification of 25-hydroxy cholesterol by GC- or LC-mass spectrometry. 25-hydroxy Cholesterol is a side-chain substituted oxysterol derived from dietary cholesterol that inhibits the cleavage of sterol regulatory element binding proteins (SREBPs) to suppress endogenous cholesterol synthesis in various cell types. It has been implicated in a variety of metabolic events including cholesterol homeostasis and atherosclerosis as well as antitumor activities as it has been shown to induce apoptosis through down-regulation of Bcl-2 expression and activation of caspases. Immunomodulating capabilities have also been observed as the oxysterol can act as a LXR-RXR ligand coupling cholesterol synthesis to T cell proliferation, can reduce (EC50 ~ 65 nM) IgA production by B cells in response to IL-2, and can suppress differentiation of monocytes into macrophages.
