Summary
Since there are data to indicate that heavy exercise decreases insulin binding to
skeletal muscle at a point when glucose uptake is known to be augmented, we tested
the hypothesis that insulin-stimulated glucose uptake and metabolism are dissociated
from insulin binding after exercise. Therefore, insulin binding, 2-deoxy-d-glucose
(2-DOG) uptake and glucose incorporation into glycogen and glycolysis were compared
in soleus and EDL muscles of intensively exercised (2-3 h) mice and non-exercised
mice. Basal 2-DOG uptake was increased in the exercised EDL (P < 0.05) but not in
the exercised soleus (P > 0.05). However, in both muscles intense exercise increased
insulin-stimulated (0.1-16 nM) 2-DOG uptake (P < 0.05). The rates of glycogenesis
were increased in both the exercised muscles (P < 0.05) as was the rate of glycolysis
in the exercised soleus (P < 0.05). Glycolysis was not altered in the EDL (P > 0.05).
In the face of the increased 2-DOG uptake and glucose metabolism in the exercised
muscles, insulin binding was not altered in the exercised soleus muscle (P > 0.05)
and was decreased in the exercised EDL (P < 0.05). These results indicate that after
intense exercise there is a dissociation of insulin binding from insulin action on
glucose uptake and metabolism in skeletal muscles.
Key-Words
2-Deoxy-D-Glucose - Glycolysis - Glycogenesis - Soleus - EDL
