Endurance training attenuates the decrease in skeletal muscle malonyl-CoA with exercise.
Muscle malonyl-CoA has been postulated to regulate fatty acid metabolism by inhibiting carnitine palmitoyltransferase 1. In nontrained rats, malonyl-CoA decreases in working muscle during exercise. Endurance training is known to increase a muscle's reliance on fatty acids as a substrate. This study was designed to investigate whether the decline in malonyl-CoA with exercise would be greater in trained than in nontrained muscle, thereby allowing increased fatty acid oxidation. After 6-10 wk of endurance training (2 h/day) or treadmill habituation (5-10 min/day), rats were killed at rest or after running up a 15% grade at 21 m/min for 5, 20, or 60 min. Training attenuated the exercise-induced drop in malonyl-CoA and prevented the exercise-induced increase in the constant for citrate activation of acetyl-CoA carboxylase in the red quadriceps muscle of rats run for 20 and 60 min. Hence, contrary to expectations, the decrease in malonyl-CoA was less in trained than in nontrained muscle during a single bout of prolonged submaximal exercise.
Hutber
C A
CA
Zoology Department, Brigham Young University, Provo, Utah 84602, USA.
Rasmussen
B B
BB
Winder
W W
WW
D000818:Animals; D002951:Citrates / Q000378:metabolism; D004032:Diet; D007700:Kinetics; D008297:Male; D008316:Malonyl Coenzyme A / Q000097:blood / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000201:enzymology* / Q000502:physiology*; D010101:Oxygen Consumption / Q000187:drug effects / Q000502:physiology; D010805:Physical Conditioning, Animal / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D002951:Citrates; D008316:Malonyl Coenzyme A