Increased glucose and 2-deoxy-D-glucose uptake in skeletal muscle of suspended rats

The influence of 7-d of whole-body suspension (WBS) on insulin stimulated glucose and 2-deoxy-D-glucose uptake in resting skeletal muscle was examined. Differential hindlimb muscle atrophic effects characteristic of this model (soleus > gastrocnemius > EDL) were observed. WBS and control (C) rats underwent hindlimb perfusion following an overnight fast. The rate and magnitude of glucose uptake across the entire hindlimb and within six individual muscles were assessed following the addition of 150, or 1000 microU/ml insulin to a perfusate containing 10 mM glucose and 5 microCi of the non-metabolizable glucose analog 2-deoxy-D-glucose (2-DG). The rate of uptake across the hindlimbs (A-V glucose difference x perfusate flow rate) was not different between C and WBS groups in the absence of exogenous insulin. At insulin concentrations of 150 and 1000 microU/ml the hindlimb musculature of suspended rats exhibited uptakes significantly (p < 0.05) more rapid (increased initial slope of the uptake curve) and of greater magnitude (increased area under uptake curve) than that of C. Overall, no differences in basal (no exogenous insulin) 2-DG uptake were observed between C and WBS muscles. When 150 and 1000 microU/ml of insulin were added to the perfusate, individual muscles from suspended rats exhibited significantly (p < 0.05) greater accumulation of 2-DG than C. These in situ results derived from an intact hindlimb preparation are the first to correlate both total hindlimb and individual muscle glucose uptakes in suspended rats, and suggest an enhanced effect of insulin in skeletal muscle of suspended rats.(ABSTRACT TRUNCATED AT 250 WORDS)