| Autor: |
Ingemar Björkhem, Dieter Lütjohann, Ulf Diczfalusy, Lars Ståhle, Gunvor Ahlborg, John Wahren |
| Jazyk: |
angličtina |
| Rok vydání: |
1998 |
| Předmět: |
|
| Zdroj: |
Journal of Lipid Research, Vol 39, Iss 8, Pp 1594-1600 (1998) |
| Druh dokumentu: |
article |
| ISSN: |
0022-2275 |
| DOI: |
10.1016/S0022-2275(20)32188-X |
| Popis: |
We have previously demonstrated that the brain contains about 80% of the 24S-hydroxycholesterol in the human body and that there is a net flux of this steroid from the brain into the circulation (Lütjohann, D. et al. 1996. Proc. Natl. Acad. Sci. USA. 93: 9799–9804). Combining previous data with new data on 12 healthy volunteers, the arteriovenous difference between levels of this oxysterol in the internal jugular vein and in a peripheral artery was found to be –10.2 ± 2.8 ng/ml (mean ± SEM) corresponding to a net flux of 24S-hydroxycholesterol from the brain of about 6.4 mg/24 h. The arteriovenous difference between levels of 24S-hydroxycholesterol in the hepatic vein and a peripheral artery of 12 other volunteers was found to be 7.4 ± 2.2 ng/ml, corresponding to a hepatic uptake of about 7.6 mg/24 h. The concentrations of 24S-hydroxycholesterol in the renal vein were about the same as those in a peripheral artery, indicating that a renal elimination is not of importance. Intravenously injected deuterium-labeled racemic 24-hydroxycholesterol was eliminated from the circulation of two human volunteers with half-lives of 10 h and 14 h, respectively. A positive correlation was found between the levels of circulating cholesterol and 24S-hydroxycholesterol. The results are consistent with a cerebral origin of most of the circulating 24S-hydroxycholesterol and suggest that the liver is the major eliminating organ. It is concluded that conversion into 24S-hydroxycholesterol is a quantitatively important mechanism for elimination of cholesterol from human brain. The possibility is discussed that circulating levels of 24S-hydroxycholesterol can be used as a marker for pathological and/or developmental changes in the brain.—Björkhem, I., D. Lütjohann, U. Diczfalusy, L. Ståhle, G. Ahlborg, and J. Wahren. Cholesterol homeostasis in human brain: turnover of 24S-hydroxycholesterol and evidence for a cerebral origin of most of this oxysterol in the circulation. |
| Databáze: |
Directory of Open Access Journals |
| Externí odkaz: |
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