Notes: 7α-Hydroxy-3-oxocholest-4-enoic acid-d3 is intended for use as an internal standard for the quantification of 7α-hydroxy-3-oxocholest-4-enoic acid by GC- or LC-MS. 7α-Hydroxy-3-oxocholest-4-enoic acid is a metabolite of the endogenous liver X receptor (LXR) agonist 25(R)-27-hydroxy cholesterol (Item No. 14790) and a bile acid precursor.{64911,64912} Plasma levels of 7α-hydroxy-3-oxocholest-4-enoic acid are reduced in patients with relapsing-remitting multiple sclerosis (RRMS).{64912}