INFLUENCE OF THE SYMPATHETIC NERVOUS-SYSTEM ON INSULIN SENSITIVITY AND ADIPOSE-TISSUE METABOLISM - A STUDY IN SPINAL CORD-INJURED SUBJECTS

To evaluate insulin sensitivity and adipose tissue metabolism, seven s pinal cord-injured (SCI) subjects (age, 43 +/- 6 years; body mass inde x, 22.8 +/- 1.4; mean +/- SE) and their seven siblings (age, 45 +/- 6 years; body mass index, 24.8 +/- 0.8) were studied using oral glucose (100-g) tolerance tests (OGTTs), euglycemic insulin clamps (insulin in fusion, 1 mU/kg.min), and microdialysis of the subcutaneous tissue. Bl ood glucose and insulin after oral glucose were significantly increase d in SCI subjects as compared with their siblings. During insulin clam ping, plasma adrenaline increased significantly in controls, but not i n SCI subjects. However, the rates of glucose production (2.02 +/- 0.3 6 v 1.59 +/- 0.09 mg/kg min) and utilization (5.13 +/- 0.71 v 5.78 +/- 0.34) were similar in the two groups. Furthermore, interstitial subcu taneous glycerol and lactate concentrations before and after oral gluc ose were similar in the two groups, even in neurally decentralized tis sue with broken connection between the central nervous system and peri pheral sympathetic nerves. The data suggest that (1) well-mobilized SC I subjects show minor insulin resistance, and (2) sympathetic nervous activity has a minor influence on adipose tissue metabolism in the pos tabsorptive state, but may affect insulin sensitivity during euglycemi c clamping. Copyright (C) 1995 by W.B. Saunders Company