colestolone colestolone colestolone (inn, usan), also known as 5α-cholest-8(14)-en-3β-ol-15-one, is a potent inhibitor of sterol biosynthesis which is described as a hypocholesterolemic (lipid-lowering) agent. it was first reported in 1977 and was studied until at least 1988, but was never introduced for medical use. colestoloneclinical dataother names5α-cholest-8(14)-en-3β-ol-15-one; 3β-hydroxy-5α-cholest-8(14)-en-15-oneidentifiers iupac name (3s,5s,10s,13r,17r)-3-hydroxy-10,13-dimethyl-17-(6-methylheptan-2-yl)-1,2,3,4,5,6,7,9,11,12,16,17-dodecahydrocyclopentaphenanthren-15-one cas number50673-97-7pubchem cid39756chemspider39756unii5p8396t5xfcomptox dashboard (epa)dtxsid6046212 chemical and physical dataformulac27h44o2molar mass400.647 g·mol−13d model (jsmol)interactive image smiles cc(c)cccc(c)1cc(=o)c2=c3cc4c(cc4(c3cc12c)c)o inchi inchi=1s/c27h44o2/c1-17(2)7-6-8-18(3)23-16-24(29)25-21-10-9-19-15-20(28)11-13-26(19,4)22(21)12-14-27(23,25)5/h17-20,22-23,28h,6-16h2,1-5h3/t18?,19-,20-,22?,23+,26-,27+/m0/s1key:linvvmhrtusxhl-ndnsgufdsa-n colestolone has been found to significantly reduce serum levels of cholesterol both in animals and in humans. it inhibits multiple relatively early-stage steps in cholesterol biosynthesis such as hmg-coa reductase and does not appear to affect any late-stage steps (after squalene, specifically). unlike late-stage cholesterol biosynthesis inhibitors like triparanol and azacosterol, no accumulation of sterols has been observed in animals treated with colestolone, suggesting that it does not share the toxicity of late-stage cholesterol biosynthesis inhibitors. in addition to its potent inhibition of cholesterol biosynthesis, it is notable that colestolone also happens to serve as a precursor of cholesterol, and is efficiently converted into it in rat liver homogenates and upon oral administration to rats.