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 of 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.
- Research Organization:
- Veterans Administration Medical Center, Minneapolis, MN (USA)
- OSTI ID:
- 6758303
- Journal Information:
- Hepatol.; (United States), Vol. 8:5
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
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