Human skeletal muscle malonyl-coa at rest and during prolonged
submaximal exercise.
Odland, L. Maureen, George J. F. Heigenhauser, Gary D. Lopaschuk,
Lawrence L. Spriet.
Department of Human Biology and Nutritional Sciences, University of
Guelph, Guelph, Ontario, N1G 2W1 and Department of Medicine, McMaster
University, Hamilton, Ontario, L8N 3Z5 and Cardiovascular Disease
Research Group, Lipid and Lipoprotein Research Group, Department of
Pediatrics and Pharmacology, Faculty of Medicine, University of
Alberta, Edmonton, Alberta, T6G 2S2, CANADA
APStracts 2:0253E, 1995.
Previous literature has indicated that contraction-induced decreases
in malonyl-CoA are instrumental in the regulation of fatty acid
oxidation during prolonged submaximal exercise. This study was
designed to measure malonyl-CoA in human vastus lateralis muscle at
rest and during submaximal exercise. Eight males and 1 female cycled
for 70 min (10 min at 40% and 60 min at 65% VO2 max). Needle biopsies
were obtained at rest, 10 min, 20 min, and 70 min of exercise.
Malonyl-CoA content in pre-exercise biopsy samples determined by HPLC
was 1.53 +/- 0.18 _mol x kg-1 dry mass (dm). Malonyl-CoA content did
not change significantly during exercise (1.39 +/- 0.21 at 10 min,
1.46 +/- 0.14 at 20 min and 1.22 +/- 0.15 _mol x kg-1 dm at 70 min).
In contrast, malonyl-CoA content determined by HPLC in perfused rat
red gastrocnemius muscle decreased significantly during 20 min of
stimulation at 0.7 Hz (3.44 +/- 0.54 to 1.64 +/- 0.23 nmol x g-1 dm,
(n=9)). We conclude that human skeletal muscle malonyl-CoA content 1)
is less than reported in rat skeletal muscle at rest, 2) does not
decrease with prolonged submaximal exercise, and 3) is not predictive
of increased fatty acid oxidation during exercise.
Received 26 October 1995; accepted in final form 5 December 1995.
APS Manuscript Number E514-5.
Article publication pending Am. J. Physiol. (Endocrinol. Metab.).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 23 December 95