Journal of Applied Physiology, Vol 69, Issue 2 686-693, Copyright © 1990 by American Physiological Society
Effects of exercise on insulin-induced hypoglycemia
J. Arogyasami, R. K. Conlee, C. L. Booth, R. Diaz, T. Gregory, S. Sephton, G. I. Wilson and W. W. Winder
Department of Zoology, Brigham Young University, Provo, Utah 84602.
The purpose of this study was to determine the effect of exercise on the
rate of onset of hypoglycemia induced by infusion of excess insulin (0.8
mU.min-1.100 g-1). Rats were either fasted overnight (FS) or fed ad libitum
(FD). FS rats were killed after 5, 10, or 15 min of infusion at rest or
after running on the treadmill at 21 m/min and 15% grade. FD rats were
killed after 10, 20, or 40 min of infusion at rest or after exercise. Rats
were also killed 15 min postexercise for FS and 60 or 120 min postexercise
for FD with continued insulin infusion. The progressive decline in blood
glucose was not altered by exercise in the FS rats. FD rats showed a
significant difference due to exercise only after 40 min (rest 4.2 +/- 0.3
mM, exercise 3.2 +/- 0.2 mM). A significant postexercise repletion of
glycogen was observed in red vastus and soleus muscles of FD rats despite
the decreasing blood glucose values. These data indicate that exercise
accelerates the rate of development of hypoglycemia in FD rats. In the FS
rats, where the rate of decline in blood glucose was greater, exercise had
no effect on the time course of development of hypoglycemia.
