Sex differences in lipolysis-regulating mechanisms in overweight subjects: effect of exercise intensity.

Abstract : OBJECTIVE: To explore sex differences in the regulation of lipolysis during exercise, the lipid-mobilizing mechanisms in the subcutaneous adipose tissue (SCAT) of overweight men and women were studied using microdialysis. RESEARCH METHODS AND PROCEDURES: Subjects matched for age, BMI, and physical fitness performed two 30-minute exercise bouts in a randomized fashion: the first test at 30% and 50% of their individual maximal oxygen uptake (Vo(2max)) and the second test at 30% and 70% of their Vo(2max). RESULTS: In both groups, an exercise-dependent increment in extracellular glycerol concentration (EGC) was observed. Whatever the intensity, phentolamine [alpha-adrenergic receptor (AR) antagonist] added to a dialysis probe potentiated exercise-induced lipolysis only in men. In a probe containing phentolamine plus propranolol (beta-AR antagonist), no changes in EGC occurred when compared with the control probe when exercise was performed at 30% and 50% Vo(2max). A significant reduction of EGC (when compared with the control probe) was observed in women at 70% Vo(2max). At each exercise power, the plasma non-esterified fatty acid and glycerol concentrations were higher in women. Exercise-induced increase in plasma catecholamine levels was lower in women compared with men. Plasma insulin decreased and atrial natriuretic peptide increased similarly in both groups. DISCUSSION: Overweight women mobilize more lipids (assessed by glycerol) than men during exercise. alpha(2)-Anti-lipolytic effect was functional in SCAT of men only. The major finding is that during low-to-moderate exercise periods (30% and 50% Vo(2max)), lipid mobilization in SCAT relies less on catecholamine-dependent stimulation of beta-ARs than on an increase in plasma atrial natriuretic peptide concentrations and the decrease in plasma insulin.
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Obesity (Silver Spring, Md.), 2007, 15 (9), pp.2245-55. 〈10.1038/oby.2007.267〉
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Soumis le : mercredi 12 août 2009 - 09:58:22
Dernière modification le : jeudi 27 août 2009 - 10:35:47

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Cédric Moro, Fabien Pillard, Isabelle De Glisezinski, François Crampes, Claire Thalamas, et al.. Sex differences in lipolysis-regulating mechanisms in overweight subjects: effect of exercise intensity.. Obesity (Silver Spring, Md.), 2007, 15 (9), pp.2245-55. 〈10.1038/oby.2007.267〉. 〈inserm-00409689〉

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