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Title: Metabolic fate of dietary carnitine in human adults: Identification and quantification of urinary and fecal metabolites

Abstract

Results of kinetic and pharmacokinetic studies have suggested that dietary carnitine is not totally absorbed and is in part degraded in the gastrointestinal tract of humans. To determine the metabolic fate of dietary carnitine in humans, we administered orally a tracer dose of methyl-{sup 3}H L-carnitine with a meal to subjects who had been adapted to a low-carnitine diet or a high-carnitine diet. Urinary and fecal excretion of radiolabeled carnitine and metabolites was monitored for 5 to 11 d following administration of the test dose. Total radioactive metabolites excreted ranged from 13 to 34% (low carnitine diet) and 27 to 46% (high carnitine diet) of the ingested tracer. Major metabolites found were ({sup 3}H)trimethylamine N-oxide (8 to 39% of the administered dose; excreted primarily in urine) and ({sup 3}H)gamma-butyrobetaine (0.09 to 8% of the administered dose; excreted primarily in feces). Urinary excretion of total carnitine was 42 to 95% (high carnitine diet) and 190 to 364% (low carnitine diet) of intake. These results indicate that oral carnitine is 54 to 87% bioavailable from normal Western diets; the percentage of intake absorbed is related to the quantity ingested.

Authors:
;  [1]
  1. Univ. of Iowa College of Medicine, Iowa City (USA)
Publication Date:
OSTI Identifier:
5526653
Resource Type:
Journal Article
Journal Name:
Journal of Nutrition; (USA)
Additional Journal Information:
Journal Volume: 121:4; Journal ID: ISSN 0022-3166
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES; CARNITINE; METABOLISM; BETAINE; DIET; FECES; MAN; METABOLITES; ORAL ADMINISTRATION; SCINTILLATION COUNTING; TRACER TECHNIQUES; TRITIUM COMPOUNDS; AMINES; AMINO ACIDS; AMMONIUM COMPOUNDS; ANIMALS; BIOLOGICAL MATERIALS; BIOLOGICAL WASTES; CARBOXYLIC ACIDS; COUNTING TECHNIQUES; DRUGS; HYDROGEN COMPOUNDS; HYDROXY ACIDS; ISOTOPE APPLICATIONS; LIPOTROPIC FACTORS; MAMMALS; MATERIALS; ORGANIC ACIDS; ORGANIC COMPOUNDS; PRIMATES; QUATERNARY COMPOUNDS; VERTEBRATES; VITAMIN B GROUP; VITAMINS; WASTES; 550501* - Metabolism- Tracer Techniques

Citation Formats

Rebouche, C J, and Chenard, C A. Metabolic fate of dietary carnitine in human adults: Identification and quantification of urinary and fecal metabolites. United States: N. p., 1991. Web.
Rebouche, C J, & Chenard, C A. Metabolic fate of dietary carnitine in human adults: Identification and quantification of urinary and fecal metabolites. United States.
Rebouche, C J, and Chenard, C A. Mon . "Metabolic fate of dietary carnitine in human adults: Identification and quantification of urinary and fecal metabolites". United States.
@article{osti_5526653,
title = {Metabolic fate of dietary carnitine in human adults: Identification and quantification of urinary and fecal metabolites},
author = {Rebouche, C J and Chenard, C A},
abstractNote = {Results of kinetic and pharmacokinetic studies have suggested that dietary carnitine is not totally absorbed and is in part degraded in the gastrointestinal tract of humans. To determine the metabolic fate of dietary carnitine in humans, we administered orally a tracer dose of methyl-{sup 3}H L-carnitine with a meal to subjects who had been adapted to a low-carnitine diet or a high-carnitine diet. Urinary and fecal excretion of radiolabeled carnitine and metabolites was monitored for 5 to 11 d following administration of the test dose. Total radioactive metabolites excreted ranged from 13 to 34% (low carnitine diet) and 27 to 46% (high carnitine diet) of the ingested tracer. Major metabolites found were ({sup 3}H)trimethylamine N-oxide (8 to 39% of the administered dose; excreted primarily in urine) and ({sup 3}H)gamma-butyrobetaine (0.09 to 8% of the administered dose; excreted primarily in feces). Urinary excretion of total carnitine was 42 to 95% (high carnitine diet) and 190 to 364% (low carnitine diet) of intake. These results indicate that oral carnitine is 54 to 87% bioavailable from normal Western diets; the percentage of intake absorbed is related to the quantity ingested.},
doi = {},
journal = {Journal of Nutrition; (USA)},
issn = {0022-3166},
number = ,
volume = 121:4,
place = {United States},
year = {1991},
month = {4}
}