Transcription of the rat skeletal muscle hexokinase ii gene is
increased by acute exercise.
O'doherty, Robert M., Deanna P. Bracy, Daryl K. Granner, and David H.
Wasserman.
Department of Molecular Physiology and Biophysics, Vanderbilt
University School of Medicine, Nashville, TN, 37232
APStracts 3:0161A, 1996.
A single bout of acute exercise increases hexokinase II (HK II) mRNA
and enzyme activity (O'Doherty et al., Am. J. Physiol. 266:E171-E178,
1994). The present study addresses the mechanism of the increase in
HK II mRNA. Male rats undertook a single bout of treadmill exercise
and were then killed immediately or after a predetermined recovery
period. The gastrocnemius/plantaris muscle complex, composed of mixed
fibre-types, was excised, the nuclei were isolated, and HK I, HK II,
[beta]-actin, and [alpha]-tubulin gene transcription rates were
measured. Genomic DNA and plasmid DNA were used as positive and
negative controls, respectively. Immediately after the cessation of
30, 45 or 90 min of exercise HK II gene transcription rates were 1.3
+/- 0.3, 2.9 +/- 0.3, and 4.0 +/- 0.6 fold, respectively, above
sedentary controls. The increases after 45 and 90 min of exercise
were statistically significant (p < 0.01). One hour after the
cessation of 30 min of exercise HK II gene transcription was
significantly increased (1.40+/- 0.03 fold, p < 0.05). At all
time-points, transcription of the HK I, [beta]-actin, and [alpha]
-tubulin genes was unchanged. We conclude that the exercise-induced
increase in HK II gene transcription appears to play a major role in
the increase of HK II mRNA and activity.
Received 24 January 1996; accepted in final form 13 March 1996.
APS Manuscript Number A85-6.
Article publication pending Journal of Applied Physiology.
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 27 March 96