The oxysterols cholest-5-ene-3 beta,4 alpha-diol, cholest-5-ene-3 beta,4 beta-diol and cholestane-3 beta,5 alpha,6 alpha-triol are formed during in vitro oxidation of low density lipoprotein, and are present in human atherosclerotic plaques.
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| Abstract |
Isolated human low density lipoprotein (LDL) was oxidized with either cupric ions or soybean lipoxygenase and linoleic acid. Cholesterol oxidation products (oxysterols) were determined by isotope dilution gas chromatography-mass spectrometry. A new cholestane-3,5,6-triol isomer, cholestane-3 beta,5 alpha,6 alpha-triol, which has not previously been recognized as a cholesterol autoxidation product, was found at similar concentrations as the well-known cytotoxic cholestane-3 beta,5 alpha,6 beta-triol during both copper- and lipoxygenase-mediated LDL oxidation. Furthermore, two epimeric cholest-5-ene-3 beta,4-diols were identified in the oxidized LDL at similar concentrations. These two isomers were also identified in human atherosclerotic tissue in a ratio of 1:1 at a concentration more than 10-times higher than in non-atherosclerotic vessels. In vitro oxidation of LDL under an 18O2 atmosphere revealed that molecular oxygen was the only source of the oxygen functions at C-4 in the cholest-5-ene-3 beta,4-diols. Taken together, these findings suggest that the cholest-5-ene-3 beta,4-diols in atherosclerotic plaques are formed by autoxidation.
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| Authors | O Breuer, S Dzeletovic, E Lund, U Diczfalusy |
| Journal | Biochimica et biophysica acta (Biochim Biophys Acta) Vol. 1302 Issue 2 Pg. 145-52 (Jul 26 1996) ISSN: 0006-3002 [Print] Netherlands |
| PMID | 8695664 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't) |
| Chemical References |
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