Regional and gender variations in adipose tissue lipolysis in response to weight loss.
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/m(2). 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 alpha2-/beta-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 (beta-AR agonist), dobutamine and procaterol (beta1- and beta2-AR agonists, respectively) as well as maximal antilipolytic effects of epinephrine or UK-14304 (alpha2-AR agonist) were similar before and after weight reduction. However, both beta- and beta2-AR lipolytic sensitivities and the beta-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 alpha2-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 alpha2-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 beta2- and a decreased alpha2-AR sensitivities), in both genders.
Mauriège
P
P
Lipid Research Center, Laval University, Ste-Foy, Québec, Canada G1K 7P4.
Imbeault
P
P
Langin
D
D
Lacaille
M
M
Alméras
N
N
Tremblay
A
A
Després
J P
JP
D000243:Adenosine Deaminase / Q000494:pharmacology; D000273:Adipose Tissue / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000318:Adrenergic beta-Agonists / Q000494:pharmacology; D000328:Adult; D004280:Dobutamine / Q000494:pharmacology; D004837:Epinephrine / Q000494:pharmacology; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D007545:Isoproterenol / Q000494:pharmacology; D008066:Lipolysis / Q000187:drug effects; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000178:diet therapy / Q000378:metabolism / Q000473:pathology; D017265:Procaterol / Q000494:pharmacology; D011869:Radioligand Assay; D012727:Sex Characteristics; D014018:Tissue Distribution; D015431:Weight Loss / Q000502:physiology*
D000316:Adrenergic alpha-Agonists; D000318:Adrenergic beta-Agonists; D004280:Dobutamine; D000243:Adenosine Deaminase; D007545:Isoproterenol; D017265:Procaterol; D004837:Epinephrine