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Metabolism of 4 bet...
Metabolism of 4 beta -hydroxycholesterol in humans
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Bodin, Karl (författare)
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Andersson, Ulla (författare)
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Rystedt, Eva (författare)
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- Ellis, Eva (författare)
- Karolinska Institutet
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- Norlin, Maria (författare)
- Uppsala universitet,Biokemi,Pharm Biochemistry
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Pikuleva, Irina (författare)
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- Eggertsen, Gösta (författare)
- Karolinska Institutet
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- Björkhem, Ingemar (författare)
- Karolinska Institutet
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- Diczfalusy, Ulf (författare)
- Karolinska Institutet
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(creator_code:org_t)
- 2002
- 2002
- Engelska.
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 277:35, s. 31534-31540
- Relaterad länk:
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https://urn.kb.se/re...
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https://doi.org/10.1...
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http://kipublication...
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Abstract
Ämnesord
Stäng
- One of the major oxysterols in the human circulation is 4 beta-hydroxycholesterol formed from cholesterol by the drug-metabolizing enzyme cytochrome P450 3A4. Deuterium-labeled 4 beta-hydroxycholesterol was injected into two healthy volunteers, and the apparent half-life was found to be 64 and 60 h, respectively. We have determined earlier the half-lives for 7 alpha-, 27-, and 24-hydroxycholesterol to be approximately 0.5, 0.75, and 14 h, respectively. Patients treated with certain antiepileptic drugs have up to 20-fold increased plasma concentrations of 4 beta-hydroxycholesterol. The apparent half-life of deuterium-labeled 4 beta-hydroxycholesterol in such a patient was found to be 52 h, suggesting that the high plasma concentration was because of increased synthesis rather than impaired clearance. 4 beta-Hydroxycholesterol was converted into acidic products at a much slower rate than 7 alpha-hydroxycholesterol in primary human hepatocytes, and 4 beta-hydroxycholesterol was 7 alpha-hydroxylated at a slower rate than cholesterol by recombinant human CYP7A1. CYP7B1 and CYP39A1 had no activity toward 4 beta-hydroxycholesterol. These results suggest that the high plasma concentration of 4 beta-hydroxycholesterol is because of its exceptionally slow elimination, probably in part because of the low rate of 7 alpha-hydroxylation of the steroid. The findings are discussed in relation to a potential role of 4 beta-hydroxycholesterol as a ligand for the nuclear receptor LXR.
Ämnesord
- NATURVETENSKAP -- Kemi (hsv//swe)
- NATURAL SCIENCES -- Chemical Sciences (hsv//eng)
Nyckelord
- Chemistry
- Kemi
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