Measurement of cholesterol 7 alpha-hydroxylase activity with selected ion monitoring.
Formation of 7 alpha-hydroxycholesterol by rat liver microsomes was quantitated using a gas chromatograph-mass spectrometer operated in selected ion monitoring mode. This procedure measures the mass of 7 alpha-hydroxycholesterol formed and does not require addition of labeled cholesterol to monitor...
| Main Authors: | , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
Elsevier
1981-05-01
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| Series: | Journal of Lipid Research |
| Online Access: | http://www.sciencedirect.com/science/article/pii/S0022227520373855 |
| Summary: | Formation of 7 alpha-hydroxycholesterol by rat liver microsomes was quantitated using a gas chromatograph-mass spectrometer operated in selected ion monitoring mode. This procedure measures the mass of 7 alpha-hydroxycholesterol formed and does not require addition of labeled cholesterol to monitor the reaction, since endogenous microsomal cholesterol serves as substrate for the enzyme cholesterol 7 alpha-hydroxylase. The method requires only the extraction of lipids from microsomal incubations and injection of a small fraction of this extract into the apparatus. Microsomes from normal rat livers incubated for different periods were found to yield increased 7 alpha-hydroxycholesterol with time. |
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| ISSN: | 0022-2275 |