Gln27Glu polymorphism in the beta2 adrenergic receptor gene and lipid metabolism during exercise in obese women

BACKGROUND: The Glu27Glu genotype in the beta-2-adrenergic receptor (ADRB2) is associated with fat mass, body mass index and obesity in females. In our population, we previously found an association of higher body mass index (BMI) among women who reported more physical activity and carried the Glu27 allele as compared to non carriers with the same level of activity. OBJECTIVE: To examine the lipid metabolism differences, both at rest and during submaximal exercise in ADRB2 Glu27Glu vs Gln27Gln obese women. SUBJECTS: Eight obese women with the Glu27Glu genotype (age, 43±5 y; body mass index (BMI), 31.7±0.9 kg/m2; percentage fat mass, 42.0±1.3; WHR, 0.83±0.02; and VO2max, 21.6±0.9 ml/kg/min) were compared with seven obese women with the Gln27Gln genotype (age, 43±5 y; BMI, 33.9±1.3 kg/m2; percentage fat mass, 41.6±1.2; WHR, 0.83±0.02; and VO2max, 20.6±0.8 ml/kg/min). MEASUREMENTS: The ADRB2 polymorphism was identified by PCR-RFLP. Respiratory quotient was determined by indirect calorimetry at baseline, during 1 h of walking on a treadmill and 1 h after the exercise. Plasma triglycerides, glycerol, FFA, hydroxybutyrate, glucose and lactate were assayed by spectrophotometric methods. Insulin, leptin and progesterone were measured by radioimmunoassay. Adrenaline and noradrenaline were quantified by high performance liquid chromatography. RESULTS: The ADRB2 Glu27Glu subjects had lower plasma glycerol (P=0.047) and lower hydroxybutyrate (P=0.001) throughout the study than the Gln27Gln group. Plasma triglycerides (P=0.001), lactate (P<0.05) and serum insulin (P<0.05) remained higher in the Glu27Glu group vs the Gln27Gln group. The respiratory quotient (RQ) was higher in the Glu27Glu obese women along the study (P=0.046), and fat oxidation was significantly lower in this group during the recovery (P=0.048). The other variables did not differ statistically between groups. CONCLUSION: These data suggest that both lipolysis and fat oxidation promoted by an acute submaximal exercise intervention could be blunted in the polymorphic ADRB2 Glu27Glu group of our female obese population

Protein Kinase A Regulatory Subunits in Human Adipose Tissue: Decreased R2B Expression and Activity in Adipocytes From Obese Subjects

OBJECTIVE—In human adipocytes, the cAMP-dependent pathway mediates signals originating from β-adrenergic activation, thus playing a key role in the regulation of important metabolic processes, i.e., lipolysis and thermogenesis. Cyclic AMP effects are mainly mediated by protein kinase A (PKA), whose R2B regulatory isoform is the most expressed in mouse adipose tissue, where it protects against diet-induced obesity and fatty liver development. The aim of the study was to investigate possible differences in R2B expression, PKA activity, and lipolysis in adipose tissues from obese and nonobese subjects

Protein Kinase A Regulatory Subunits in Human Adipose Tissue: Decreased R2B Expression and Activity in Adipocytes From Obese Subjects

OBJECTIVE—In human adipocytes, the cAMP-dependent pathway mediates signals originating from β-adrenergic activation, thus playing a key role in the regulation of important metabolic processes, i.e., lipolysis and thermogenesis. Cyclic AMP effects are mainly mediated by protein kinase A (PKA), whose R2B regulatory isoform is the most expressed in mouse adipose tissue, where it protects against diet-induced obesity and fatty liver development. The aim of the study was to investigate possible differences in R2B expression, PKA activity, and lipolysis in adipose tissues from obese and nonobese subjects

Gln27Glu polymorphism in the beta2 adrenergic receptor gene and lipid metabolism during exercise in obese women

BACKGROUND: The Glu27Glu genotype in the beta-2-adrenergic receptor (ADRB2) is associated with fat mass, body mass index and obesity in females. In our population, we previously found an association of higher body mass index (BMI) among women who reported more physical activity and carried the Glu27 allele as compared to non carriers with the same level of activity. OBJECTIVE: To examine the lipid metabolism differences, both at rest and during submaximal exercise in ADRB2 Glu27Glu vs Gln27Gln obese women. SUBJECTS: Eight obese women with the Glu27Glu genotype (age, 43±5 y; body mass index (BMI), 31.7±0.9 kg/m2; percentage fat mass, 42.0±1.3; WHR, 0.83±0.02; and VO2max, 21.6±0.9 ml/kg/min) were compared with seven obese women with the Gln27Gln genotype (age, 43±5 y; BMI, 33.9±1.3 kg/m2; percentage fat mass, 41.6±1.2; WHR, 0.83±0.02; and VO2max, 20.6±0.8 ml/kg/min). MEASUREMENTS: The ADRB2 polymorphism was identified by PCR-RFLP. Respiratory quotient was determined by indirect calorimetry at baseline, during 1 h of walking on a treadmill and 1 h after the exercise. Plasma triglycerides, glycerol, FFA, hydroxybutyrate, glucose and lactate were assayed by spectrophotometric methods. Insulin, leptin and progesterone were measured by radioimmunoassay. Adrenaline and noradrenaline were quantified by high performance liquid chromatography. RESULTS: The ADRB2 Glu27Glu subjects had lower plasma glycerol (P=0.047) and lower hydroxybutyrate (P=0.001) throughout the study than the Gln27Gln group. Plasma triglycerides (P=0.001), lactate (P<0.05) and serum insulin (P<0.05) remained higher in the Glu27Glu group vs the Gln27Gln group. The respiratory quotient (RQ) was higher in the Glu27Glu obese women along the study (P=0.046), and fat oxidation was significantly lower in this group during the recovery (P=0.048). The other variables did not differ statistically between groups. CONCLUSION: These data suggest that both lipolysis and fat oxidation promoted by an acute submaximal exercise intervention could be blunted in the polymorphic ADRB2 Glu27Glu group of our female obese population