Racial difference in Acylation Stimulating Protein (ASP) correlates to triglyceride in non-obese and obese African American and Caucasian women

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Effect of breakfast glycemic index on metabolic responses during rest and exercise in overweight and non-overweight adolescent girls

The metabolic responses to mixed breakfast meals with different glycemic indexes (GI) and their effects on substrate metabolism during exercise in adolescent girls have not been examined. The interaction with weight status also warrants investigation. This study investigated the effect of mixed breakfast meals containing high GI (HGI) or low GI (LGI) carbohydrates on metabolic responses and fat oxidation during rest and exercise in overweight (OW) and non-overweight (NO) adolescent girls. A total of 8 OW and 12 NO adolescent girls consumed an isoenergetic HGI (GI=73) or LGI (GI=44) breakfast 120 min before completing a 30-min treadmill walk at 50% O2peak. Peak blood glucose concentration was higher for HGI compared with LGI in OW (P=0.023), but not NO (P>0.05) girls. Blood glucose total area under the curve (TAUC) was 13% higher in HGI compared with LGI in OW (P=0.006), but only 4% higher in NO (P=0.072) girls. Plasma insulin data were loge transformed (lninsulin). Plasma lninsulin concentrations were not different between HGI and LGI (P>0.05). Peak plasma lninsulin concentration (P=0.016) and TAUC (P=0.001) were greater in OW than NO girls. Fat oxidation during postprandial rest and exercise was not different between breakfasts (P>0.05). The elevated glycemic response in HGI compared with LGI was more pronounced in OW girls, suggesting a reduced ability to cope with the metabolic demands of the HGI, but not LGI, breakfast. Manipulation of breakfast GI did not alter fat oxidation during rest or subsequent moderate intensity exercise in OW and NO adolescent girls

Efeito do índice glicêmico no gasto energético e utilização de substrato energético antes e depois de exercício cicloergométrico Effect of glycemic index on energy expenditure and energy substrate utilization before and after exercise on a stationary bicycle

OBJETIVO: No presente artigo, avaliou-se o efeito do consumo, durante cinco dias consecutivos, de refeições diferindo em índice glicêmico no gasto energético, na oxidação de substrato energético e no consumo excessivo de oxigênio após o exercício. MÉTODOS: Participaram do estudo 15 homens bem treinados, com idade de M=24,4, DP=3,70 anos e consumo máximo de oxigênio (VO2max) de M=70,00, DP=5,32mL (kg.min)-1. Após o consumo das refeições, os participantes permaneceram por noventa minutos no calorímetro indireto Deltatrac®, para a avaliação dos parâmetros metabólicos. A seguir, foi realizado um exercício de 85 a 95% da frequência cardíaca máxima, em três estágios de dez minutos. Os parâmetros metabólicos foram novamente avaliados durante os sessenta minutos pós-exercício. RESULTADOS: Os tratamentos aplicados no estudo não afetaram o gasto energético, o consumo excessivo de oxigênio e a oxidação lipídica após o exercício. Entretanto, a taxa de oxidação de gordura foi maior durante os noventa minutos no grupo que consumiu a refeição de alto índice glicêmico antes do exercício, em relação ao da refeição de baixo índice glicêmico. Além disso, a taxa de oxidação lipídica do período pós-prandial foi inferior àquela obtida no período pós-exercício. CONCLUSÃO: Os resultados sugerem que enquanto o consumo de refeições de baixo índice glicêmico pode não exercer efeito benéfico, a realização de exercício físico pode promover maior oxidação lipídica e consequentemente afetar a redução do teor de gordura corporal.<br>OBJECTIVE: The present study assessed, on 5 consecutive days, the effect of consuming meals with different glycemic indices on energy expenditure, energy substrate oxidation and excessive oxygen consumption after exercise. METHODS: A total of 15 well trained men aged M=24.4, SD=3.70 years with a mean body mass index of M=21.97, SD=1.46 kg/m² and maximum oxygen uptake (VO2max) of M=70.00, SD= 5.32 mL(kg.min)-1 participated in the study. After the meal, the participants remained 90 minutes in the indirect calorimeter Deltatrac® for assessment of the metabolic parameters. Next, they exercised at 85-95% of their maximum heart rate in three bouts of 10 minutes. The metabolic parameters were reassessed within the 60 minutes following the exercise. RESULTS: The study treatments did not affect energy expenditure, excessive oxygen consumption or fat oxidation after exercise. However, the rate of fat oxidation in the 90 minutes that followed the meal was higher in those who consumed the high-glycemic index meal than in those who consumed the low-glycemic index meal. Moreover, the postprandial fat oxidation rate was lower than that observed after the exercise. CONCLUSION: These results suggest that, while the consumption of low-glycemic index meals may not have beneficial effects, exercise can promote greater fat oxidation and, consequently, reduce body fat

Decreased expression of adipogenic genes in obese subjects with type 2 diabetes

OBJECTIVE: Our objective was to delineate the potential role of adipogenesis in insulin resistance and type 2 diabetes. Obesity is characterized by an increase in adipose tissue mass resulting from enlargement of existing fat cells (hypertrophy) and/or from increased number of adipocytes (hyperplasia). The inability of the adipose tissue to recruit new fat cells may cause ectopic fat deposition and insulin resistance. RESEARCH METHODS AND PROCEDURES: We examined the expression of candidate genes involved in adipocyte proliferation and/or differentiation [ CCAAT/enhancer-binding protein (C/EBP) , C/EBP , GATA domain-binding protein 3 (GATA3), C/EBP , peroxisome proliferator-activated receptor (PPAR) 2, signal transducer and activator of transcription 5A (STAT5A), Wnt-10b, tumor necrosis factor , sterol regulatory element-binding protein 1c (SREBP1c), 11 beta-hydroxysteroid dehydrogenase, PPARG angiopoietin-related protein (PGAR), insulin-like growth factor 1, PPAR coactivator 1 , PPAR coactivator 1 , and PPAR ] in subcutaneous adipose tissue from 42 obese individuals with type 2 diabetes and 25 non-diabetic subjects matched for age and obesity. RESULTS: Insulin sensitivity was measured by a 3-hour 80 mU/m2 per minute hyperinsulinemic glucose clamp (100 mg/dL). As expected, subjects with type 2 diabetes had lower glucose disposal (4.9 1.9 vs. 7.5 2.8 mg/min per kilogram fat-free mass; p < 0.001) and larger fat cells (0.90 0.26 vs. 0.78 0.17 m; p = 0.04) as compared with obese control subjects. Three genes (SREBP1c, p < 0.01; STAT5A, p = 0.02; and PPAR 2, p = 0.02) had significantly lower expression in obese type 2 diabetics, whereas C/EBP only tended to be lower (p = 0.07). DISCUSSION: This cross-sectional study supports the hypothesis that impaired expression of adipogenic genes may result in impaired adipogenesis, potentially leading to larger fat cells in subcutaneous adipose tissue and insulin resistance.Severine G. Dubois, Leonie K. Heilbronn, Steven R. Smith, Jeanine B. Albu, David E. Kelley, Eric Ravussin and the Look AHEAD Adipose Research Grou