AJP - Regulatory, Integrative and Comparative Physiology, Vol 251, Issue 6 1151-R1155, Copyright © 1986 by American Physiological Society
Liver glycogenolysis during exercise in adrenodemedullated male and female rats
W. W. Winder, S. F. Loy, D. S. Burke and S. J. Hawkes
Previous studies have shown that adrenodemedullation has no effect on the
rate of liver glycogenolysis during exercise in male rats. Mature female
rats have been reported to have a higher hepatic beta-adrenergic receptor
activity than do male rats of the same age. The present study was
undertaken to determine the role of plasma epinephrine in stimulating liver
glycogenolysis during exercise in female rats. Both male and female rats
were adrenodemedullated or sham operated. Three weeks later rats were run
for 60 min at 21 m/min up a 15% grade. The rate of liver glycogenolysis
during exercise was not affected by adrenodemedullation in either female
rats or male rats. Hepatic adenosine 3',5'-cyclic monophosphate increased
to approximately the same extent in sham operated as in adrenodemedullated
female rats during exercise. Adrenodemedullation caused a significant
reduction in the amount of glycogen utilized by the soleus muscle and in
the degree of hyperglycemia during exercise. We conclude that epinephrine
is unessential for stimulation of liver glycogenolysis during exercise in
either male or female rats.
