Journal of Applied Physiology, Vol 56, Issue 4 1060-1064, Copyright © 1984 by American Physiological Society
Regulation of fatty acid biosynthesis in rats by physical training
R. Scorpio, R. L. Rigsby, D. R. Thomas and B. D. Gardner
Physical training in the form of long-term nonexhaustive daily exercise was
studied as a means of regulating fatty acid biosynthesis. Male rats were
required to swim for periods up to 90 min/day. The exercise was carried out
6 days/wk for approximately 11 wk. Hepatic fatty acid biosynthesis and
acetyl-CoA carboxylase [acetyl-CoA: CO2 ligase (EC 6.4.1.2)] activities
were compared with nonexercised rats. At the end of the training period the
exercised rats had a lower rate of fatty acid biosynthesis activity and a
lower rate of acetyl-CoA carboxylase activity. The difference in acetyl-CoA
carboxylase activity was due to a change in maximal velocity with no
significant change in the Michaelis constant for acetyl-CoA. Untrained rats
were subjected to a single bout of exercise. They also exhibited lower
rates of fatty acid biosynthesis and acetyl-CoA carboxylase activities
compared with nonexercised rats. However, the lower rates of these enzyme
activities were sustained longer in the physically trained rats compared
with the exercised untrained rats after the cessation of exercise. These
results implicate acetyl-CoA carboxylase as a control site in the
regulation of hepatic fatty acid biosynthesis by both physical training and
acute exercise in rats. Possible inhibitory mechanisms are discussed.
