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

Abstract

OBJECTIVE: 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.

SUBJECTS: Eleven obese non-diabetic males, aged 41.5±5.7 7 (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.

DESIGN: 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 β β-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.

RESULTS: 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.

CONCLUSION:

The present study shows that aerobic training induced an increase in the response of plasma and subcutaneous adipose tissue concentration of glycerol to β-adrenergic stimulation. The effect of an agent acting at the post-receptor level (theophylline) in SCAT was not modified by training.