Sympathetic modulation of lipolysis in subcutaneous adipose tissue: Effects of gender and energy restriction

To investigate the differences in the regulation of lipolysis between male and female obese subjects in vivo, we used an in situ microdialysis techniq ue before and after 3 weeks of energy restriction. Using this method, we ex amined glycerol, glucose, and lactate responses after 5 minutes of epinephr ine stimulation in the adipose tissues. Glycerol releases after the perfusi on of phentolamine, orciprenaline, and propranolol were also studied. Sixte en subjects were studied (8 men, 8 women, 35 to 45 years of age, body mass index 38 to 50 kg/m(2)), In women, epinephrine provoked a greater glycerol release than in men in both abdominal and femoral regions (P < .05). In men and women there was a significant decrease in the concentration of glucose and a significant increase in lactate concentration after epinephrine stim ulation (P < .001). After 3 weeks of energy restriction, glycerol release a fter epinephrine stimulation was greater in both sexes than that observed b efore energy restriction (P < .05). Both phentolamine and orciprenaline sti mulated the release of glycerol (P < .01); phentolamine had a higher effect in women, while propranolol had no effect on glycerol release in both sexe s. In summary, we have demonstrated that epinephrine provoked a greater lip olytic response in obese women in both abdominal and femoral adipose tissue s. The lipolytic response was further enhanced after 3 weeks of energy rest riction in each gender. The decrease in glucose concentration suggests that glucose may be reutilized for synthesis into new triacylglycerol, Knowledg e about the sensitivity to lipolytic agents in subcutaneous adipose tissue may provide potential new approaches for modulating the lipolytic responses of subcutaneous adipose tissue differently in men and women.