Endurance training changes in lipolytic responsiveness of obese adipose tissue

The aim of this study was to investigate the effect of aerobic exercise tra ining on the lipolytic response of adipose tissue in obese subjects. Thirte en men (body mass index = 36.9 +/- 1.3 kg/m(2)) were submitted to aerobic p hysical training on a cycloergometer (30-45 min, 4 days a wk) for 3 mo. Adi pocyte sensitivity to the action of catecholamines and insulin was studied in vitro before and after training. Training induced a decrease in the perc entage of fat mass (P < 0.05) without changing the body weight. Basal lipol ysis and hormone-sensitive lipase activity were significantly decreased aft er training (P < 0.05). The lipolytic effects of epinephrine, isoprenaline (beta-adrenoceptor agonist), and dobutamine (beta(1)-adrenoceptor agonist) were significantly increased (P < 0.05) but not those of procaterol (beta(2 )-adrenoceptor agonist). The antilipolytic effects of alpha(2)-adrenoceptor and insulin were significantly decreased (P < 0.05). Lipolysis stimulation by agents acting at the postreceptor level was unchanged after training. I n conclusion, aerobic physical training in obese male subjects modifies adi pose tissue lipolysis through an enhancement of beta-adrenergic response an d a concomitant blunting of adipocyte antilipolytic activity.