Regulation of diurnal variation of cholesterol 7α-hydroxylase (CYP7A1) activity in healthy subjects

Title:

Regulation of diurnal variation of cholesterol 7α-hydroxylase (CYP7A1) activity in healthy subjects

Creator:

Kovář, J., Martin Leníček, Zimolová, M., Libor Vítek, Milan Jirsa, and Jan Piťha

Identifier:

https://cdk.lib.cas.cz/client/handle/uuid:2ccb08f4-689e-4ff3-8ca9-bd54302e7d45
uuid:2ccb08f4-689e-4ff3-8ca9-bd54302e7d45

Subject:

Fyziologie člověka a srovnávací fyziologie, cholesterol, inzulin, glukóza, insulin, glucose, cholesterol 7α-hydroxylase, bile acid, cholestyramine, 14, and 612

Type:

article, články, model:article, and TEXT

Format:

print

Description:

Cholesterol 7α-hydroxylase (CYP7A1), the key regulatory enzyme of bile acid synthesis, displays a pronounced diurnal variation. To better understand the regulation of CYP7A1 activity, three daylong examinations were carried out in 12 healthy men. The concentrations of 7α-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., J. Kovář ... [et al.]., and Obsahuje bibliografii a bibliografické odkazy

Language:

English

Rights:

http://creativecommons.org/licenses/by-nc-sa/4.0/
policy:public

Source:

Physiological research | 2010 Volume:59 | Number:2

Harvested from:

CDK

Metadata only:

false