Dissociation Between Insulin Binding and Glucose Utilization After Intense Exercise in Mouse Skeletal Muscles

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