Regional and gender variations in adipose tissue lipolysis in response to weight loss

Abstract

Catecholamine-induced lipolysis was investigated in 32 obese subjects (14 men and 18 premenopausal women), aged 36–50 years, whose body mass index ranged from 30 to 42 kg/m2. Isolated subcutaneous (subc) abdominal and femoral adipocytes were studied before and after a 15-week weight reducing program, during which mean body weight loss averaged 9 vs. 10 kg in women and men, respectively (P < 0.0001). Participants were re-examined when they were weight-stable. Fat cell weight decreased by about 15–20% in both depots (P values ranging from 0.01 to 0.05). Epinephrine (mixed α2-/β-adrenoceptor (AR) agonist) induced antilipolysis at low concentrations and a net lipolytic response at higher doses, irrespective of subjects' fatness and anatomic location of fat. Basal lipolysis, maximal lipolytic responses to isoprenaline (β-AR agonist), dobutamine and procaterol (β1- and β2-AR agonists, respectively) as well as maximal antilipolytic effects of epinephrine or UK-14304 (α2-AR agonist) were similar before and after weight reduction. However, both β- and β2-AR lipolytic sensitivities and the β-AR density were increased in both genders after weight reduction, this effect being more marked in subc abdominal than in femoral adipocytes (P values ranging from 0.001 to 0.05). The α2-AR antilipolytic sensitivity was reduced in adipose cells from both regions in women, but only in subc abdominal adipocytes in men (P < 0.05), although the α2-AR density remained unchanged after weight reduction. In conclusion, a moderate weight loss leads to a higher adipose cell lipolytic efficiency which is associated with changes at receptor levels (mainly an increased β2- and a decreased α2-AR sensitivities), in both genders.—Mauriège, P., P. Imbeault, D. Langin, M. Lacaille, N. Alméras, A. Tremblay, and J. P. Després. Regional and gender variations in adipose tissue lipolysis in response to weight loss. J. Lipid Res. 1999. 40: 1559–1571.

Keywords

• computed tomography
• catecholamines
• adrenoceptors
• hormone-sensitive lipase