PathwayStep1629 PathwayStep1623 PathwayStep1618 PathwayStep1613 PathwayStep1643 PathwayStep1554 PathwayStep1557 PathwayStep1583 PathwayStep1597 PathwayStep1514 PathwayStep1451 Cholesterol is hydroxylated to 7alpha-hydroxycholesterol by CYP7A1 Lanosterol is oxidatively demethylated to 4,4-dimethylcholesta-8(9),14,24-trien-3beta-ol 25-hydroxycholesterol is 7alpha-hydroxylated by CYP7B1 Cholesterol is hydroxylated to 27-hydroxycholesterol by CYP27 Androstenedione is converted to estrone by Aromatase (CYP19A1) 11-deoxycortisol is oxidised to cortisol by CYP11B1 21-hydroxylation of progesterone to form 11-deoxycorticosterone 20alpha,22beta-hydroxycholesterol is cleaved by CYP11A1 to yield pregnenolone and isocaproaldehyde Hydroxylation of pregnenolone to form 17alpha-hydroxypregnenolone Cholesterol is hydroxylated to 24-hydroxycholesterol by CYP46A1 24-hydroxycholesterol is 7alpha-hydroxylated to yield cholest-5-ene-3beta,7alpha,24-triol PathwayStep2629 PathwayStep2631 PathwayStep2630 Endogenous sterols A number of CYPs take part in cholesterol biosynthesis and elimination, thus playing an important role in maintaining cholesterol homeostasis. Under normal physiological conditions, cholesterol intake (diet or synthesized de novo from acetyl CoA) equals cholesterol elimination (degraded to bile salts, secreted in bile and used in steroid hormone synthesis). These processes are under tight regulatory control and any disruption leads to increased cholesterol levels resulting in cardiovacular disease. The CYPs involved in cholesterol homeostasis could serve as potential targets for cholesterol-lowering drugs. Authored: Jassal, B, 2008-05-19 12:57:01 Edited: Jassal, B, 2008-05-19 12:57:01 Pubmed15102545 Pubmed16584116 Pubmed16872679 Reactome Database ID Release 43211976 Reactome, http://www.reactome.org ReactomeREACT_13812 Reviewed: D'Eustachio, P, 2008-05-28 08:30:54 Sterols are 12-hydroxylated by CYP8B1 11-deoxycorticosterone is oxidised to corticosterone by CYP11B2 CYP1B1 4-hydroxylates estradiol-17beta