AJP - Regulatory, Integrative and Comparative Physiology, Vol 247, Issue 5 780-R785, Copyright © 1984 by American Physiological Society
Mechanism of training-induced attenuation of postexercise ketosis
M. A. Beattie and W. W. Winder
We have examined the roles of liver glycogen and malonyl coenzyme A (CoA)
in determining the degree of postexercise ketosis in endurance-trained and
nontrained rats. Three groups of rats were run on a treadmill for 90 min:
trained (2 h/day, 6 wk) and food restricted to 5.5 g/100 g body wt the
night before the 90-min exercise bout (group 1), nontrained fed ad libitum
(group 2), and nontrained food restricted (same as trained) (group 3).
Liver glycogen was 34 +/- 5, 24 +/- 2, and 7 +/- 2 mg/g in groups 1, 2, and
3, respectively, at the end of exercise. At the end of exercise and during
the postexercise period the blood 3-hydroxybutyrate concentration in group
3 was significantly higher than in groups 1 or 2. No difference was
observed between groups 1 and 2 in blood 3-hydroxybutyrate. Hepatic malonyl
CoA was decreased to the same extent in all rats during exercise but
remained depressed only in the glycogen-depleted group 3 rats in the
postexercise period. These data suggest that the differences in degree of
ketonemia in the postexercise period (but not during exercise) were due to
lower hepatic malonyl CoA in group 3 rats.
