Journal of Applied Physiology, Vol 66, Issue 3 1099-1103, Copyright © 1989 by American Physiological Society
Cardiac triacylglycerol content and lipase activity during recovery from exercise
B. Podbielski and W. K. Palmer
Department of Physical Education, University of Illinois, Chicago 60680.
Female rats swam for 2-h to determine the temporal relationship between
triglyceride (TG) repletion and TG lipase activity in the heart during
recovery from exercise. Immediately after the exercise, plasma free fatty
acids (FFA) had increased from a resting value of 0.44 +/- 0.04 to 0.84 +/-
0.04 mM. Heart TG concentration was reduced 75%, whereas the glycogen level
was decreased 34% below control. TG lipase activity was elevated 33% above
control activity. One hour after the end of the exercise, lipolytic
activity was still 26% above control and did not return to the resting
level until the 4th h of recovery. The cardiac TG concentration was back to
control levels by the 2nd h after the swim. Plasma FFA concentrations
remained elevated during the first 4 h of recovery and were back to the
control level by h 8. Cardiac glycogen was "supercompensated" during
recovery h 1 and 2 and returned to the preexercise level by h 4. These data
indicate that TG is being synthesized in the heart while lipolytic enzyme
activity is elevated above control levels. This points out that the rate of
TG synthesis is in excess of the hydrolysis. Since plasma FFA
concentrations are elevated during periods of augmented TG synthesis,
substrate availability, namely plasma FFA, may play a key role in
regulating the size of the intracellular TG pool.
