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Title: Effects of bile acid administration on bile acid synthesis and its circadian rhythm in man

In man bile acid synthesis has a distinct circadian rhythm but the relationship of this rhythm to feedback inhibition by bile acid is unknown. We measured bile acid synthesis as release of 14CO2 from (26-14C)cholesterol every 2 hr in three normal volunteers during five separate 24-hr periods. Data were fitted by computer to a cosine curve to estimate amplitude and acrophase of the circadian rhythm. In an additional six volunteers, we measured synthesis every 2 hr from 8:00 a.m. to 4:00 p.m. only. During the control period, amplitude (expressed as percentage of mean synthesis) averaged 52% and acrophase averaged 6:49 a.m. During administration of ursodeoxycholic acid (15 mg per kg per day), synthesis averaged 126% of baseline (p less than 0.1), amplitude averaged 43% and acrophase averaged 6:20 a.m. During administration of chenodeoxycholic acid (15 mg per kg per day), synthesis averaged 43% of baseline (p less than 0.001), amplitude averaged 53% and acrophase averaged 9:04 a.m. Addition of prednisone to this regimen of chenodeoxycholic acid to eliminate release of 14CO2 from corticosteroid hormone synthesis resulted in a mean amplitude of 62% and a mean acrophase of 6:50 a.m., values very similar to those in the baseline period. Administration ofmore » prednisone alone also did not significantly alter the baseline amplitude (40%) or acrophase (6:28 a.m.). We conclude that neither chenodeoxycholic acid nor ursodeoxycholic acid significantly alters the circadian rhythm of bile acid synthesis in man.« less
Authors:
;
Publication Date:
OSTI Identifier:
6758303
Resource Type:
Journal Article
Resource Relation:
Journal Name: Hepatol.; (United States); Journal Volume: 8:5
Research Org:
Veterans Administration Medical Center, Minneapolis, MN (USA)
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; BILE ACIDS; BIOSYNTHESIS; CHOLIC ACID; BIOCHEMICAL REACTION KINETICS; PREDNISONE; CARBON 14 COMPOUNDS; CARBON DIOXIDE; CHOLESTEROL; DAILY VARIATIONS; TRACER TECHNIQUES; ADRENAL HORMONES; CARBON COMPOUNDS; CARBON OXIDES; CARBOXYLIC ACIDS; CHALCOGENIDES; CORTICOSTEROIDS; GLUCOCORTICOIDS; HYDROXY COMPOUNDS; ISOTOPE APPLICATIONS; KETONES; KINETICS; LABELLED COMPOUNDS; ORGANIC ACIDS; ORGANIC COMPOUNDS; OXIDES; OXYGEN COMPOUNDS; PREGNANES; REACTION KINETICS; STEROIDS; STEROLS; SYNTHESIS; VARIATIONS 550201* -- Biochemistry-- Tracer Techniques