Journal of Applied Physiology, Vol 75, Issue 4 1502-1506, Copyright © 1993 by American Physiological Society
Effect of estradiol on the temporal pattern of exercise-induced tissue glycogen depletion in male rats
T. P. Rooney, Z. V. Kendrick, J. Carlson, G. S. Ellis, B. Matakevich, S. M. Lorusso and J. A. McCall
Biokinetics Research Laboratory, Temple University, Philadelphia, Pennsylvania 19122.
The effect of 17 beta-estradiol 3-benzoate (10 micrograms.01 ml of
sunflower oil-1 x 100 g body wt-1) on the temporal pattern of
exercise-induced tissue glycogen depletion and tissue lipid availability
during submaximal treadmill running was determined in male rats. Animal
were administered estradiol or oil for 5 days and were then time matched
for motorized treadmill running for 30, 60, 90, or 120 min. Significant
depletion of liver, soleus muscle, and red and white vastus lateralis
muscle tissue glycogen occurred in oil-administered animals run between 30
and 120 min. The greatest extent of tissue glycogen depletion occurred
during the first 30 min of exercise with the rate of glycogen depletion
slowing between 30 and 120 min of exercise. Administration of estradiol
attenuated the temporal pattern of glycogen depletion in both liver and
muscle tissues. Significant depletion of red and white vastus glycogen of
estradiol-administered animals did not occur until 90 and 120 min of
exercise, respectively. Administration of estradiol significantly increased
resting plasma free fatty acids and red and white vastus triacylglycerol
content. These data indicate that estradiol administration for 5 days
resulted in significant glycogen sparing of liver and muscle tissues during
submaximal treadmill running for up to 120 min by altering the temporal
pattern of glycogen depletion of male rats secondary to an
estradiol-mediated increase in availability of lipid substrate during
exercise.
