Article

Diabetologia

, Volume 47, Issue 1, pp 23-30

Disassociation of muscle triglyceride content and insulin sensitivity after exercise training in patients with Type 2 diabetes

  • C. R. BruceAffiliated withExercise Metabolism Group, School of Medical Sciences, RMIT University
  • , A. D. KriketosAffiliated withGarvan Institute of Medical Research, St. Vincent’s Hospital
  • , G. J. CooneyAffiliated withGarvan Institute of Medical Research, St. Vincent’s Hospital
  • , J. A. HawleyAffiliated withExercise Metabolism Group, School of Medical Sciences, RMIT University Email author 

Abstract

Aim/hypothesis

We determined the effect of exercise training on insulin sensitivity and muscle lipids (triglyceride [TGm] and long-chain fatty acyl CoA [LCACoA] concentration) in patients with Type 2 diabetes.

Methods

Seven patients with Type 2 diabetes and six healthy control subjects who were matched for age, BMI, % body fat and VO2peak participated in a 3 days per week training program for 8 weeks. Insulin sensitivity was determined pre- and post-training during a 120 min euglycaemic-hyperinsulinaemic clamp and muscle biopsies were obtained before and after each clamp. Oxidative enzyme activities [citrate synthase (CS), β-hydroxy-acyl-CoA (β-HAD)] and TGm were determined from basal muscle samples pre- and post training, while total LCACoA content was measured in samples obtained before and after insulin-stimulation, pre- and post training.

Results

The training-induced increase in VO2peak (~20%, p<0.01) was similar in both groups. Compared with control subjects, insulin sensitivity was lower in the diabetic patients before and after training (~60%; p<0.05), but was increased to the same extent in both groups with training (~30%; p<0.01). TGm was increased in patients with Type 2 diabetes (170%; p<0.05) before, but was normalized to levels observed in control subjects after training. Basal LCACoA content was similar between groups and was unaltered by training. Insulin-stimulation had no detectable effect on LCACoA content. CS and β-HAD activity were increased to the same extent in both groups in response to training (p<0.001).

Conclusion/interpretation

We conclude that the enhanced insulin sensitivity observed after short-term exercise training was associated with a marked decrease in TGm content in patients with Type 2 diabetes. However, despite the normalization of TGm to levels observed in healthy individuals, insulin resistance was not completely reversed in the diabetic patients.

Keywords

Muscle triacylglycerol long-chain fatty acyl CoA insulin resistance oxidative capacity