The subcutaneous lipolytic response to regional neural stimulation is reduced in obese women

Disturbed fat tissue metabolism with a reduction of the Lipolytic rate coul d be an important pathogenetic factor in obesity. Lipolysis of the subcutan eous tissue of the thigh is partly under neural control and can be increase d by intraneural stimulation of the lateral cutaneous femoral nerve in lean women. In the present study, we tested whether the Lipolytic response to i ntraneural stimulation is altered in vivo in obese subjects. Seven obese wo men were examined and the results were compared with those of seven age-mat ched lean women. After an overnight fast, the lateral cutaneous femoral ner ve was intraneurally stimulated for 10 min, and the local subcutaneous lipo lytic response to this procedure was evaluated with microdialytic measureme nts of interstitial glycerol concentrations in the receptive field of the s timulated nerve fascicle. To exclude unspecific effects of stimulation, lip olysis was also controlled in a corresponding area of the contralateral leg . Intraneural stimulation produced no significant change in subcutaneous li polysis in obese women (25.7 +/- 9.7%, NS). This finding is in sharp contra st with the marked regional lipolytic response in lean women in which the s ame stimulation procedure enhanced the regional interstitial glycerol level s by 72 +/- 17% (P < 0.05) compared with the unstimulated corresponding are a of the contralateral leg. These in vivo results suggest that human obesit y is characterized by a profound unresponsiveness of the subcutaneous adipo se tissue to neurally stimulated lipolysis. This could be an important fact or in the development and treatment of obesity.