VISCERAL ADIPOSITY, INCREASED ADIPOCYTE LIPOLYSIS, AND METABOLIC DYSFUNCTION IN OBESE POSTMENOPAUSAL WOMEN

This study determines whether there are regional differences in lipoly sis and whether adipocyte lipolysis is associated with the degree of v isceral adiposity and its metabolic complications in 32 obese (28-37 k g/m(2)), nondiabetic, postmenopausal women. In vitro lipolysis was mea sured in the basal state and after addition of epinephrine (Epi), Epi plus yohimbine, Epi plus propranolol, and N-6,2'-O-dibutyryl adenosine 3',5'-cyclic monophosphate (DBcAMP) in abdominal (ABD) and gluteal (G LT) adipocytes. Upper body obese [UBO, waist-to-hip ratio (WHR) greate r than or equal to 0.80, n = 19] women had a greater intra-abdominal f at area (IA, 199 +/- 50 vs. 142 +/- 28 cm(2)) and Epi-stimulated lipol ysis (ABD: 1.60 +/- 1.10 vs. 0.95 +/- 0.54 pmol glycerol 10(6) cells(- 1). 2 h; GLT: 1.14 +/- 0.70 vs. 0.66 +/- 0.42 mu mol glycerol 10(6) ce lls(-1). 2 h) than lower body obese (LBO, WHR < 0.80, n = 13) women. T he UBO women also had lower high-density lipoprotein cholesterol (1.39 +/- 0.40 vs. 1.64 +/- 0.39 mmol/l, P < 0.05), higher plasma triglycer ides (1.89 +/- 0.48 vs. 1.44 +/- 0.56 mmol/l, P < 0.05), and higher fa sting insulin levels (154 +/- 57 vs. 118 +/- 33 pmol/l, P < 0.05) than LBO women. Basal, adrenergic receptor-mediated, and DBcAMP-stimulated lipolytic rates in ABD and GLT adipocytes were positively correlated with IA (r = 0.44-0.76, P < 0.05, n = 28). In both UBO and LBO women, Epi-stimulated lipolysis was higher (+30%, P < 0.05) in ABD than GLT a dipocytes. These results show that, in postmenopausal women, visceral obesity is associated with increased rates of lipolysis in both ABD an d GLT subcutaneous adipocytes. The findings also indicate that Epi-sti mulated lipolysis is greater in ABD than GLT adipocytes regardless of fat distribution.