7-keto Cholesterol is a bioactive sterol that can affect cholesterol homeostasis, membrane properties and cell survival. It strongly inhibits cytochrome P450 7A1 (CYP7A1), the cholesterol 7α-hydroxylase, with an IC50 = ~ 1 μM. 7-keto Cholesterol can be produced by oxidation of cholesterol associated with ethanol-mediated lipid peroxidation or photodamage. It can also be derived enzymatically by oxidation of 7-dehydrocholesterol, the immediate precursor of cholesterol, by CYP7A1, while 11β-hydroxysteroid dehydrogenase type 1 stimulates its reduction. 7-keto Cholesterol is a major oxysterol component of oxidized LDL. This compound can be used as a standard in the determination of cholesterol derivatives by GC-MS or HPLC.
