Document Detail


Regulation of diurnal variation of cholesterol 7alpha-hydroxylase (CYP7A1) activity in healthy subjects.
MedLine Citation:
PMID:  19537927     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Cholesterol 7alpha-hydroxylase (CYP7A1), the key regulatory enzyme of bile acid synthesis, displays a pronounced diurnal variation. To better understand the regulation of CYP7A1 activity, three day-long examinations were carried out in 12 healthy men. The concentrations of 7alpha-hydroxycholest-4-en-3-one (C4), a surrogate marker of CYP7A1 activity, bile acids (BA), insulin, glucose, nonesterified fatty acids, triglycerides, and cholesterol were measured in serum in 90-min intervals from 7 AM till 10 PM. To lower and to increase BA concentration during the study, the subjects received cholestyramine and chenodeoxycholic acid (CDCA), respectively, in two examinations. No drug was used in the control examination. There was a pronounced diurnal variation of C4 concentration with a peak around 1 PM in most of the subjects. The area under the curve (AUC) of C4 concentration was five times higher and three times lower when subjects were treated with cholestyramine and CDCA, respectively. No relationship was found between AUC of C4 and AUC of BA concentration, but AUC of C4 correlated positively with that of insulin. Moreover, short-term treatment with cholestyramine resulted in about 10 % suppression of glycemia throughout the day. Our results suggest that insulin is involved in the regulation of diurnal variation of CYP7A1 activity in humans.
Authors:
J Kovár; M Lenícek; M Zimolová; L Vítek; M Jirsa; J Pitha
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Publication Detail:
Type:  Clinical Trial; Journal Article; Research Support, Non-U.S. Gov't     Date:  2009-06-19
Journal Detail:
Title:  Physiological research / Academia Scientiarum Bohemoslovaca     Volume:  59     ISSN:  0862-8408     ISO Abbreviation:  Physiol Res     Publication Date:  2010  
Date Detail:
Created Date:  2010-05-20     Completed Date:  2010-08-02     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  9112413     Medline TA:  Physiol Res     Country:  Czech Republic    
Other Details:
Languages:  eng     Pagination:  233-8     Citation Subset:  IM    
Affiliation:
Institute for Clinical and Experimental Medicine, Prague, Czech Republic. jan.kovar@medicon.cz
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MeSH Terms
Descriptor/Qualifier:
Adult
Anticholesteremic Agents / administration & dosage
Bile Acids and Salts / metabolism*
Blood Glucose / metabolism*
Chenodeoxycholic Acid / administration & dosage
Cholestenones / blood
Cholesterol / blood
Cholesterol 7-alpha-Hydroxylase / metabolism*
Cholestyramine Resin / administration & dosage
Circadian Rhythm / physiology*
Enzyme Activation
Fatty Acids, Nonesterified / blood
Gastrointestinal Agents / administration & dosage
Humans
Insulin / blood*
Male
Reference Values
Triglycerides / blood
Chemical
Reg. No./Substance:
0/Anticholesteremic Agents; 0/Bile Acids and Salts; 0/Blood Glucose; 0/Cholestenones; 0/Fatty Acids, Nonesterified; 0/Gastrointestinal Agents; 0/Triglycerides; 11041-12-6/Cholestyramine Resin; 11061-68-0/Insulin; 3862-25-7/7 alpha-hydroxy-4-cholesten-3-one; 474-25-9/Chenodeoxycholic Acid; 57-88-5/Cholesterol; EC 1.14.13.17/Cholesterol 7-alpha-Hydroxylase

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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