Journal of Applied Physiology, Vol 68, Issue 6 2451-2456, Copyright © 1990 by American Physiological Society
Triacylglycerol metabolism in rat skeletal muscle after exercise
D. Pearsall and W. K. Palmer
Department of Physical Education, University of Illinois, Chicago 60680.
The temporal relationships between triacylglycerol (TG) content and TG
lipase activity in slow-twitch (STR) and fast-twitch red (FTR) muscles were
determined in rats during recovery from a 2-h swim. Immediately after the
exercise, plasma free fatty acid (FFA) was elevated and glycogen
concentrations were decreased. TG content was decreased 40% in STR muscle
and reduced 45% in FTR muscle. The TG concentration of STR muscle increased
in a linear fashion throughout recovery so that control levels were reached
within the first 24 h after exercise. TG lipase activity of STR muscle was
elevated 36% above control immediately after the swim and continued to
increase to 84% above control 24 h after the work. In STR muscle there was
a net synthesis of TG, while lipase activity was elevated above that
measured in muscle of control rats. TG content of FTR muscle remained 45%
below control throughout the first 24 h of recovery, and TG lipase activity
increased from 26% (P greater than 0.05) greater than control immediately
after exercise to threefold above control 24 h after work. All parameters
returned to control levels by 48 h of recovery. These data indicated that a
net TG synthesis occurs in STR muscle when lipolytic activity is elevated.
In FTR muscle, however, a gradual increase in TG lipase activity that
occurs during the first 24 h of recovery accompanies a TG concentration
well below the control level throughout this same time frame.(ABSTRACT
TRUNCATED AT 250 WORDS)
