Lipolytic and nutritive blood flow response to β-adrenoceptor stimulation in situ in subcutaneous abdominal adipose tissue in obese

OBJECTIVE: beta-Adrenoceptor-mediated whole-body lipolysis is impaired in obesity. This study investigated whether local adipocyte beta-adrenergic sensitivity and changes in nutritive blood flow in subcutaneous abdominal adipose tissue contribute to this impaired response. METHODS: Three microdialysis probes were placed in the subcutaneous abdominal adipose tissue of eight obese and nine lean men. Each probe was perfused with either 0.1, 1 and 10muM isoprenaline; 1, 10 and 100muM dobutamine or 1, 10 and 100muM salbutamol, each dose for 45 min. RESULTS: At baseline, interstitial glycerol concentrations and ethanol out/in ratios were comparable between groups. During nonselective beta-, beta(1)- and beta(2)-adrenergic stimulation, interstitial glycerol concentrations increased and ethanol out/in ratios decreased similarly in obese and lean men. CONCLUSION: The lipolytic and nutritive blood flow response to beta(1)- beta(2)- and nonselective beta-adrenergic stimulation in situ is comparable in lean and obese male subjects. The present data suggest that a blunted beta-adrenergic sensitivity of the fat cell and an impaired local nutritive blood flow response do not contribute to the previously reported diminished whole-body beta-adrenoceptor-mediated lipolytic response in obese males.