Journal of Applied Physiology, Vol 79, Issue 3 879-885, Copyright © 1995 by American Physiological Society
Effects of acute exercise on hepatic lipogenic enzymes in fasted and refed rats
M. A. Griffiths, D. H. Baker, X. X. Yu, J. Novakofski, L. Oscai and L. L. Ji
Department of Kinesiology, University of Illinois at Urbana-Champaign 61801, USA.
The effects of an acute bout of prolonged exhaustive exercise on the
activities of hepatic lipogenic enzymes have been investigated. Male
Sprague-Dawley rats were randomly divided into three groups: fasted for 48
h without refeeding (FA) and fasted for 48 h and refed a diet high in
fructose (RF) or in cornstarch (RC). One-half of each group of rats
exercised on a treadmill at 20 m/min, 5% grade, until exhaustion and the
other half rested for the same amount of time without food. Dietary intakes
during refeeding were kept equal between the exercised and rested control
animals. Activities of all hepatic lipogenic enzymes measured, i.e., fatty
acid synthase (FAS), L-type pyruvate kinase (L-PK), ATP citrate lyase,
malic enzyme, and glucose-6-phosphate dehydrogenase, were induced
dramatically by fasting-refeeding and were significantly higher in the RF
than in the RC rats (P < 0.05). FAS activity was increased 19- and
39-fold, respectively, in the RC and RF rats compared with the FA rats.
Exercise decreased FAS activity to approximately one-third of the resting
control value in both RC and RF rats (P < 0.05) but not in FA rats. L-PK
activity was elevated by 55% in RC and 100% in RF rats compared with FA
rats (P < 0.05). FA and RF rats also showed a reduction of L-PK activity
with exercise. No significant alteration of other lipogenic enzymes was
observed after exercise.(ABSTRACT TRUNCATED AT 250 WORDS)
