Triacylglycerol metabolism in rat skeletal muscle after exercise.
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)
Pearsall
D
D
Department of Physical Education, University of Illinois, Chicago 60680.
Palmer
W K
WK
D000818:Animals; D005230:Fatty Acids, Nonesterified / Q000097:blood; D006003:Glycogen / Q000378:metabolism; D008049:Lipase / Q000378:metabolism; D008297:Male; D009132:Muscles / Q000378:metabolism*; D005082:Physical Exertion / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D013550:Swimming; D014280:Triglycerides / Q000378:metabolism*
D005230:Fatty Acids, Nonesterified; D014280:Triglycerides; D006003:Glycogen; D008049:Lipase