Metabolism of cholesteryl palmitate by rat brain in vitro; formation of cholesterol epoxides and cholestane-3β,5α,6β-triol
Incubation of [4-14C] cholesteryl palmitate with the 12,000 g supernatant fraction of adult rat brain fortified with an NADPH-generating system and β-mercaptoethylamine resulted in formation (2–5%) of more polar metabolites characterized as a mixture of cholesterol-5,6-epoxides. Under extended incub...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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Elsevier
1973-11-01
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| Series: | Journal of Lipid Research |
| Subjects: | |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0022227520368425 |
| _version_ | 1818743092829749248 |
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| author | Charles M. Martin Harold J. Nicholas |
| author_facet | Charles M. Martin Harold J. Nicholas |
| author_sort | Charles M. Martin |
| collection | DOAJ |
| description | Incubation of [4-14C] cholesteryl palmitate with the 12,000 g supernatant fraction of adult rat brain fortified with an NADPH-generating system and β-mercaptoethylamine resulted in formation (2–5%) of more polar metabolites characterized as a mixture of cholesterol-5,6-epoxides. Under extended incubation conditions, cholestane-3β,5α,6β-triol was isolated as the major end product of the incubations. Free [4-14C]cholesterol incubated under similar conditions was not oxidized, whereas oxidation of [4-14C]cholesteryl palmitate appeared to be dependent upon hydrolysis of the ester by the rat brain microsomal subcellular fraction. Elimination of the NADPH-generating system or the addition of EDTA to the incubation mixture inhibited epoxide formation, suggesting that the products are derived from an NADPH-dependent enzymatic lipoperoxidation mechanism. The in vitro conversion of [4-14C] cholesterol-5α,6α-epoxide to cholestane-3β,5α,6β-triol was also demonstrated in rat brain subcellular fractions in the absence of added cofactors. |
| first_indexed | 2024-12-18T02:22:55Z |
| format | Article |
| id | doaj.art-cc3ad4b5b07e44398722f8c3a33f787e |
| institution | Directory Open Access Journal |
| issn | 0022-2275 |
| language | English |
| last_indexed | 2024-12-18T02:22:55Z |
| publishDate | 1973-11-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Journal of Lipid Research |
| spelling | doaj.art-cc3ad4b5b07e44398722f8c3a33f787e2022-12-21T21:24:06ZengElsevierJournal of Lipid Research0022-22751973-11-01146618624Metabolism of cholesteryl palmitate by rat brain in vitro; formation of cholesterol epoxides and cholestane-3β,5α,6β-triolCharles M. Martin0Harold J. Nicholas1Institute of Medical Education and Research and Department of Biochemistry, St. Louis University School of Medicine, St. Louis, Missouri 63104Institute of Medical Education and Research and Department of Biochemistry, St. Louis University School of Medicine, St. Louis, Missouri 63104Incubation of [4-14C] cholesteryl palmitate with the 12,000 g supernatant fraction of adult rat brain fortified with an NADPH-generating system and β-mercaptoethylamine resulted in formation (2–5%) of more polar metabolites characterized as a mixture of cholesterol-5,6-epoxides. Under extended incubation conditions, cholestane-3β,5α,6β-triol was isolated as the major end product of the incubations. Free [4-14C]cholesterol incubated under similar conditions was not oxidized, whereas oxidation of [4-14C]cholesteryl palmitate appeared to be dependent upon hydrolysis of the ester by the rat brain microsomal subcellular fraction. Elimination of the NADPH-generating system or the addition of EDTA to the incubation mixture inhibited epoxide formation, suggesting that the products are derived from an NADPH-dependent enzymatic lipoperoxidation mechanism. The in vitro conversion of [4-14C] cholesterol-5α,6α-epoxide to cholestane-3β,5α,6β-triol was also demonstrated in rat brain subcellular fractions in the absence of added cofactors.http://www.sciencedirect.com/science/article/pii/S0022227520368425brain cholesterolcholesterol oxidation |
| spellingShingle | Charles M. Martin Harold J. Nicholas Metabolism of cholesteryl palmitate by rat brain in vitro; formation of cholesterol epoxides and cholestane-3β,5α,6β-triol Journal of Lipid Research brain cholesterol cholesterol oxidation |
| title | Metabolism of cholesteryl palmitate by rat brain in vitro; formation of cholesterol epoxides and cholestane-3β,5α,6β-triol |
| title_full | Metabolism of cholesteryl palmitate by rat brain in vitro; formation of cholesterol epoxides and cholestane-3β,5α,6β-triol |
| title_fullStr | Metabolism of cholesteryl palmitate by rat brain in vitro; formation of cholesterol epoxides and cholestane-3β,5α,6β-triol |
| title_full_unstemmed | Metabolism of cholesteryl palmitate by rat brain in vitro; formation of cholesterol epoxides and cholestane-3β,5α,6β-triol |
| title_short | Metabolism of cholesteryl palmitate by rat brain in vitro; formation of cholesterol epoxides and cholestane-3β,5α,6β-triol |
| title_sort | metabolism of cholesteryl palmitate by rat brain in vitro formation of cholesterol epoxides and cholestane 3β 5α 6β triol |
| topic | brain cholesterol cholesterol oxidation |
| url | http://www.sciencedirect.com/science/article/pii/S0022227520368425 |
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