Impaired in vivo stimulation of lipolysis in adipose tissue by selective beta(2)-adrenergic agonist in obese adolescent girls

Studies performed in adults with long-standing obesity suggest a reduced li polytic sensitivity to catecholamines in subcutaneous abdominal adipose tis sue (AT). We used microdialysis to study the in situ lipolytic effects of d obutamine (selective beta (1)-agonist) and terbutaline (selective beta (2)- agonist) on glycerol release (lipolytic index) in abdominal subcutaneous AT in 10 obese girls aged 13-17 years, BMI 38 +/- 2.1 kg/m(2) and in 7 lean g irls aged 11-17 years, BMI 21 +/- 1.1 kg/m(2), and compared them with 10 ob ese women aged 21-39 years, BMI 36 +/- 1,6 kg/m(2) and 10 lean women aged 1 8-42 years, BMI 21 +/- 0.4 kg/m(2). Terbutaline at 10(-6) mol/l stimulated glycerol release more efficiently in lean girls than in obese girls (peak r esponse similar to 350 vs. 150% of control, P < 0.01). At the lower concent ration of agonist, no significant difference was seen. In women, terbutalin e was more effective in lean than in obese women in stimulating glycerol re lease at both 10(-8) mol/l (peak response lean <similar to>175% vs, obese 1 25% of control) and 10(-6) mol/l (similar to 300 vs. 150% of control, P < 0 .05). No significant difference in glycerol release between obese and lean girls or women was detected with selective <beta>(1)-stimulation. Our data demonstrate a specific impairment in the capacity of beta (2)-adrenergic ag onists to promote lipolysis in subcutaneous abdominal adipose tissue of obe se adolescent girls and women. Thus, decreased mobilization of fat during a ctivation of the adrenergic system might be present early in the developmen t of adolescent obesity.