Adipocyte Biology
Obesity (2008) 16 7, 1487–1492. doi:10.1038/oby.2008.242
Circulating IL-6 Concentrations and Abdominal Adipocyte Isoproterenol-stimulated Lipolysis in Women
Anne-Sophie Morisset1,2, Céline Huot3, Denis Légaré3 and André Tchernof1,2
- 1Molecular Endocrinology and Oncology Research Center, Laval University Medical Research Center and Laval University, Québec City, Québec, Canada
- 2Department of Nutrition, Laval University, Québec City, Québec, Canada
- 3Gynaecology Unit, Laval University Medical Research Center, Québec City, Québec, Canada
Correspondence: André Tchernof (andre.tchernof@crchul.ulaval.ca)
Received 12 June 2007; Accepted 6 December 2007; Published online 24 April 2008.
Abstract
Objective:
To examine the association of plasma interleukin-6 (IL-6) concentrations with adiposity and fat cell metabolism in women.
Methods and Procedures:
Omental (OM) and subcutaneous (SC) adipose tissue samples were obtained from 48 healthy women (age: 47 
5 years, BMI: 26.9 5.3 kg/m2) 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 
r 0.65, P < 0.05) and OM (0.36 r 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 0.07).
Discussion:
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.
