Expression of AdipoR1 In Vivo in Skeletal Muscle Is Independently Associated With Measures of Truncal Obesity in Middle-Aged Caucasian Men
- Junlong Zhang, PHD1,
- Helen Holt, BM, MRCP (U.K.)1,
- Chunli Wang1,
- Omar H. Hadid2 and
- Christopher D. Byrne, PHD, FRCPATH, FRCP1
- 1Endocrinology & Metabolism Unit, Developmental Origins of Health and Disease Division, School of Medicine, University of Southampton, Southampton, U.K.
- 2Ophthalmology Department, Newcastle upon Tyne Trust, Newcastle upon Tyne, U.K.
- Address correspondence and reprint requests to Prof. C.D. Byrne, Endocrinology & Metabolism Unit, Developmental Origins of Health and Disease Division, University of Southampton, Level F, Central Block, Mailpoint 113, Southampton General Hospital, Southampton, SO16 6YD, U.K. E-mail:
- AdipoR, adiponectin receptor
- DEXA, dual-energy X-ray absorbtiometry
- FFA, free fatty acid
- MRI, magnetic resonance imaging
The insulin-sensitizing effect of adiponectin (1–4) is mediated via adiponectin receptors (AdipoR1 and AdipoR2) (5). AdipoR1 is abundantly expressed in skeletal muscle, whereas AdipoR2 is also expressed in the liver, with lower levels of expression in skeletal muscle (5). Both receptors are expressed in adipose tissue (6) and pancreatic β-cells (7). It has been shown recently that expression of AdipoRs in human skeletal muscle is correlated with insulin sensitivity (8). Because central obesity is associated with insulin resistance, we have undertaken detailed measurements of body fatness with bioimpedance, dual-energy X-ray absorbtiometry (DEXA), and five-slice magnetic resonance imaging (MRI) through the abdomen. We have determined whether expression of AdipoRs was associated with body fatness and in particular with measures of central obesity.
RESEARCH DESIGN AND METHODS
The study protocol was undertaken with local research ethics committee approval, and informed consent was obtained from all subjects. Fifteen middle-aged (42–64, mean age 53.2 ± 5.8 years), healthy Caucasian men with a wide range of BMIs (21–39 kg/m2, 30.63 ± 5.48) were recruited. Waist circumference was measured over bare skin midway between the costal margin and the iliac crest. Percentage of body fat was measured using bioelectrical impedance (Bodystat 1500; Bodystat, Isle of Man, U.K.). DEXA scanning was undertaken on a Delphi W instrument (Hologic, Bedford, MA) using a standard …