Effect of a long-duration physical exercise on fat cell lipolytic responsiveness to adrenergic agents and insulin in obese men

OBJECTIVE: The aim of the study was to investigate whether a long-lasting bout of exercise modifies the lipolytic β- and antilipolytic-α2-adrenergic effect and the antilipolytic effect of insulin in obese subjects. DESIGN: Biopsies of abdominal subcutaneous adipose tissue were performed before and immediately after 2 h exercise (at 50% of VO2max) on an ergometric bicycle. SUBJECTS: Nine healthy obese male subjects (mean age 38.0±3.5 y; mean body mass index (BMI) 35.6±3.9 kg/m2) were included in the experiment. METHODS: The lipolytic responsiveness to adrenaline, isoprenaline (β-adrenergic agonist), UK-14304 (α2-adrenergic agonist) and insulin was studied in the isolated fat cell obtained by biopsies of subcutaneous adipose tissue from the peri-umbilical region before and after exercise. RESULTS: After exercise, an increase was observed in spontaneous lipolytic rate, and in the lipolytic effect of isoprenaline, but no modification in the lipolytic action of adrenaline. Antilipolytic effects of UK-14304 and insulin were not changed by the single bout of exercise. CONCLUSION: A single bout of long-term exercise increased the responsiveness of adipose tissue to β-adrenergic stimulation of lipolysis in obese subjects.