Endurance training increases the beta-adrenergic lipolytic response in subcutaneous adipose tissue in obese subjects.

Abstract

The aim of this study was to assess, by longitudinal follow-up, the influence of aerobic training on the in vivo lipolytic activity of adipose tissue in obese male subjects. Eleven obese non-diabetic males, aged 41.5+/-5.77 (range 27-49 y) with body mass index (BMI) 36.5+/-4.5 kg/m2 (range 29.4-47.1 kg/m2) participated in the study. Subjects took part in a 12-week aerobic training program. Before and after training, microdialysis of abdominal subcutaneous adipose tissue (SCAT) was carried out, using perfusion with graded doses of the beta-adrenergic agonist isoprenaline and a single dose of the phosphodiesterase inhibitor theophylline. In addition, the response of plasma glycerol and free fatty acids (FFAs) to intravenous infusion of graded doses of isoprenaline was tested. The training did not induce significant weight loss and promoted an increase in maximum aerobic capacity (P<0.05). The increase of extracellular glycerol in SCAT in response to isoprenaline perfusion was enhanced after the training (P<0.05), while no change in the response of interstitial glycerol to theophylline action was observed. The training did not elicit a change in the isoprenaline-induced changes of blood flow in adipose tissue. The increases of plasma FFAs and glycerol in response to intravenous isoprenaline infusion, were significantly enhanced after training. The present study shows that aerobic training induced an increase in the response of plasma and subcutaneous adipose tissue concentration of glycerol to beta-adrenergic stimulation. The effect of an agent acting at the post-receptor level (theophylline) in SCAT was not modified by training.