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Effect of intravenous L ‐carnitine on carnitine homeostasis and fuel metabolism during exercise in humans
Author(s) -
Brass Eric P,
Hoppel Charles L,
Hiatt William R
Publication year - 1994
Publication title -
clinical pharmacology and therapeutics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.941
H-Index - 188
eISSN - 1532-6535
pISSN - 0009-9236
DOI - 10.1038/clpt.1994.85
Subject(s) - carnitine , skeletal muscle , medicine , endocrinology , metabolism , chemistry , glycogen , crossover study , homeostasis , placebo , alternative medicine , pathology
This study was undertaken to challenge the hypothesis that short‐term administration of carnitine during exercise can modify skeletal muscle carnitine homeostasis and fuel metabolism in normal humans. With a randomized, blinded, crossover design, subjects received carnitine or placebo at the start of a bicycle ergometer exercise session. During the 2 hours after intravenous administration of 185 µmol/kg carnitine, carnitine kinetics could be described with a central compartment volume of distribution of 200 ml/kg, a total clearance from this compartment of 1.9 ml/min/kg, and a renal clearance of 1.3 ml/min/kg. Carnitine administration had no effect on muscle total carnitine content or the workload‐dependent accumulation of acylcarnitines in skeletal muscle. Carnitine had no effect on the respiratory exchange ratio, muscle lactate accumulation, plasma lactate concentration, muscle glycogen utilization, or plasma β‐hydroxybutyrate concentration during exercise. Thus the skeletal muscle carnitine pool is segregated from dramatic changes in the plasma carnitine pool, and short‐term administration of carnitine has no significant effect on fuel metabolism during exercise in humans. Clinical Pharmacology and Therapeutics (1994) 55 , 681–692; doi: 10.1038/clpt.1994.85