Circulating IL-6 concentrations and abdominal adipocyte isoproterenol-stimulated lipolysis in women.
OBJECTIVE
To examine the association of plasma interleukin-6 (IL-6) concentrations with adiposity and fat cell metabolism in women.


METHODS
Omental (OM) and subcutaneous (SC) adipose tissue samples were obtained from 48 healthy women (age: 47+/-5 years, BMI: 26.9+/-5.3 kg/m(2)) undergoing gynecological surgeries. Total and visceral adiposity were assessed by dual-energy X-ray absorptiometry and computed tomography, respectively. Measures of adipocyte lipolysis (basal, isoproterenol-, forskolin-, and cyclic dibutyryl-adenosine monophosphate (AMP)-stimulated) and adipose tissue lipoprotein lipase (LPL) activity were obtained. Plasma IL-6 was measured by radioimmunoassay.


RESULTS
Plasma IL-6 was positively correlated with total body fat mass (r=0.32, P<0.05), SC adipose tissue area (r=0.35, P<0.05), SC adipocyte diameter (r=0.30, P<0.05), and a trend was observed with visceral adipose tissue area (r=0.20, P<0.07). Plasma IL-6 was positively correlated with glycerol released in response to isoproterenol (10(-5) to 10(-8) mol/l) by isolated SC (0.31 <or= r <or= 0.65, P<0.05) and OM (0.36 <or= r <or= 0.40, P<0.02) adipocytes, independent of menopausal status. No correlation was found with LPL activity. A subsample of women with high plasma IL-6 (n=10) was matched with women with low plasma IL-6 (n=10) for total body fat mass. OM adipocyte glycerol release in response to isoproterenol (10(-5) to 10(-8) mol/l) was higher in the subsample of women with elevated plasma IL-6 (P <or= 0.07).


CONCLUSIONS
We observed that OM lipolysis was significantly higher in women with elevated plasma IL-6 for a similar body fat mass and menopausal status. These results suggest that higher circulating IL-6 concentrations are associated with increased isoproterenol-stimulated lipolysis especially in OM abdominal adipocytes in women.
Morisset
Anne-Sophie
AS
Molecular Endocrinology and Oncology Research Center, Laval University Medical Research Center and Laval University, Québec City, Québec, Canada.
Huot
Céline
C
Légaré
Denis
D
Tchernof
André
A
D015502:Absorptiometry, Photon; D017667:Adipocytes / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D050154:Adiposity; D000318:Adrenergic beta-Agonists / Q000494:pharmacology*; D000328:Adult; D048429:Cell Size; D005576:Colforsin / Q000494:pharmacology; D003430:Cross-Sectional Studies; D003563:Cyclic CMP / Q000031:analogs & derivatives / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D005990:Glycerol / Q000378:metabolism; D006801:Humans; D015850:Interleukin-6 / Q000097:blood*; D050152:Intra-Abdominal Fat / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D007545:Isoproterenol / Q000494:pharmacology*; D008066:Lipolysis / Q000187:drug effects*; D008071:Lipoprotein Lipase / Q000378:metabolism; D008875:Middle Aged; D011863:Radioimmunoassay; D050507:Subcutaneous Fat, Abdominal / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D014057:Tomography, X-Ray Computed
D000318:Adrenergic beta-Agonists; C508600:IL6 protein, human; D015850:Interleukin-6; D005576:Colforsin; D003563:Cyclic CMP; C053441:dibutyryl cyclic-3',5'-cytidine monophosphate; D008071:Lipoprotein Lipase; D007545:Isoproterenol; D005990:Glycerol