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Acta Physiologica 2009; Volume 195, Supplement 667
XXXV Congress of The Spanish Society for Physiological Sciences
2/17/2009-2/20/2009
Valencia, Spain
OBR PROTEIN EXPRESSION IS REDUCED IN HUMAN OBESE SKELETAL MUSCLE: A POTENTIAL MECHANISM OF LEPTIN RESISTANCE.
Abstract number: P181
Fuentes1 T, Ara2,3 I, Guadalupe-Grau1 A, Larsen3 S, Stallknecht3 B, Olmedillas1 H, Santana1,4,5 A, Helge3 JW, Calbet1 JAL, Guerra1 B
1Department of Physical Education, University of Las Palmas de Gran Canaria, Campus Universitario de Tafira s/n, Las Palmas de Gran Canaria, 35017, Spain;
2Department of Physiatry and Nursing, University of Zaragoza, Spain;
3Copenhagen Muscle Research Centre, Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark;
4Genetic Unit, Childhood Hospital-Materno Infantil de Las Palmas, Avenida Martima, del Sur s/n, Las Palmas de Gran Canaria, 35016, Spain;
5Research Unit, Hospital de Gran Canaria Dr. Negrn, Bco Ballena s/n, Las Palmas de Gran Canaria, 35013, Spain. [email protected]
Aim:
To determine if in obesity OB-R and SOCS3 protein expression are down- and up-regulated, respectively.
Methods:
Deltoid and vastus lateralis muscle biopsies were obtained from 20 men (10 non-obese controls, (mean SEM), age: 31 5 years; height: 184 9 cm; body mass: 91 13 kg and percentage of body fat 24.8 5.8%) and 10 obese (age: 30 7 years; height: 184 8 cm; body mass: 115 8 kg and percentage of body fat 34.9 5.1%)).
Results:
Skeletal muscle OB-R170 (the long isoform of the leptin receptor) protein expression was 28 and 25% lower (both, P<0.05) in arm and leg muscles, respectively, of obese compared to controls. However, the expression of the other two OB-R isoforms (OB-R128 and OB-R98), as well as the expression of perilipin A (a protein exclusive to adipocytes) and SOCS3 protein content, was similar in control and obese subjects. Moreover, we found that the deltoid muscle has greater amount of leptin receptors than the vastus lateralis, regardless of body composition. In normal weight subjects, SOCS3 protein expression was similar in the deltoid and vastus lateralis muscles (0.97 0.18 and 1.06 0.15 arbitrary units, P=0.75). However, in obesity, SOCS3 protein expression was 36% lower and the level of STAT3 phosphorylation 2.6 fold higher in the deltoid compared to the vastus lateralis muscle (P<0.05).
Conclusion:
In obese humans there is a down-regulation of the OB-R170 protein expression in skeletal muscle; SOCS3 protein expression is increased and STAT3 phosphorylation reduced in the vastus lateralis compared to the deltoid muscle.
To cite this abstract, please use the following information:
Acta Physiologica 2009; Volume 195, Supplement 667 :P181