Kinetic compartmental analysis of carnitine metabolism in the dog

Charles J. Rebouche, Andrew G. Engel

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26 Scopus citations


This study was undertaken to quantitate the dynamic parameters of carnitine metabolism in the dog. Six mongrel dogs were given intravenous injections of l-[methyl-3H]carnitine and the specific radioactivity of carnitine was followed in plasma and urine for 19-28 days. The data were analyzed by kinetic compartmental analysis. A three-compartment, open-system model [(a) extracellular fluid, (b) cardiac and skeletal muscle, (c) other tissues, particularly liver and kidney] was adopted and kinetic parameters (carnitine flux, pool sizes, kinetic constants) were derived. In four of six dogs the size of the muscle carnitine pool obtained by kinetic compartmental analysis agreed (±5%) with estimates based on measurement of carnitine concentrations in different muscles. In three of six dogs carnitine excretion rates derived from kinetic compartmental analysis agreed (±9%) with experimentally measured values, but in three dogs the rates by kinetic compartmental analysis were significantly higher than the corresponding rates measured directly. Appropriate chromatographic analyses revealed no radioactive metabolites in muscle or urine of any of the dogs. Turnover times for carnitine were (mean ± SEM): 0.44 ± 0.05 h for extracellular fluid, 232 ± 22 h for muscle, and 7.9 ± 1.1 h for other tissues. The estimated flux of carnitine in muscle was 210 pmol/min/g of tissue. Whole-body turnover time for carnitine was 62.9 ± 5.6 days (mean ± SEM). Estimated carnitine biosynthesis ranged from 2.9 to 28 μmol/kg body wt/day. Results of this study indicate that kinetic compartmental analysis may be applicable to study of human carnitine metabolism.

Original languageEnglish (US)
Pages (from-to)60-70
Number of pages11
JournalArchives of Biochemistry and Biophysics
Issue number1
StatePublished - Jan 1983

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology


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