A metabolite of Cholesterol. It is formed from Cholesterol by the drug-metabolizing enzyme cytochrome P 450 3A4. A potential ligand for the nuclear receptor LXR and also a new endogenous CYP3A marker.
ChEBI: A oxysterol that is cholesterol in which the hydrogen at the 4beta position has been replaced by a hydroxy group. A metabolite of cholesterol formed by the drug-metabolizing enzyme cytochrome P450 3A4, it is one of the major oxysterols in
he human circulation.
4β-hydroxy cholesterol is an endogenous marker for cyp3a4/5 activity [1].cytochome p450 3a4 (cyp3a4) and cyp3a5 are important drug-metabolizing enzymes that oxidize small foreign organic molecules, such as toxins or drugs, and remove them from the body. they exhibit a large variation in hepatic expression and biological activity between different individuals. patients treated with drugs known to be strong inducers of cyp3a4/5 have highly elevated levels of 4β-hydroxycholesterol in the circulation [1].4β-hydroxy cholesterol, an endogenous oxysterol found in human circulation, is formed from cholesterol by cytochrome p450 (cyp) 3a4 and cyp3a5. in 12 different occasions during a 3-month period, the cvs for 4β-hydroxycholesterol ranged from 4.8 to 13.2% with an average cv of 7.1% at an average concentration of 30.8 ng/ml. in 24 volunteers treated with rifampicin, a strong cyp3a4/5 inducer, 4β-hydroxycholesterol increased in a dose-dependent way, while the isomer 4α-hydroycholesterol was not influenced by rifampicin treatment. these results suggested that 4β-hydroxy cholesterol is an endogenous marker for cyp3a4/5 activity [1].
[1]. diczfalusy u, kanebratt kp, bredberg e, et al. 4beta-hydroxycholesterol as an endogenous marker for cyp3a4/5 activity. stability and half-life of elimination after induction with rifampicin. br j clin pharmacol. 2009 jan;67(1):38-43.
