Effects of ingesting carbohydrate and branched-chain amino acids on markers of skeletal muscle protein synthesis of the insulin-PI3K-mTOR signal transduction pathways in response to a bout of heavy resistance exercise.
Access RightsBaylor University access only
Ferreira, Maria Pontes.
MetadataShow full item record
Purpose: To determine if activity of the MAPK-ERK or PI3K-mTOR insulin signaling pathway is increased in response to an acute lower body resistance exercise (RE) bout and supplemental BCAA + CHO or CHO ingestion. Methods: 27 recreationally trained males (20.9 y; 81.8 kg) were randomly assigned to a group: BCAA (30 g) + CHO (350 g), CHO (350 g) or placebo CON. Participants performed 4 sets of leg press and extensions at 80% 1RM to failure. Supplements were ingested at 3 time points: 30 min prior to RE, and immediately pre- and post-RE. Venous blood was sampled at baseline (Pre); 30 min post-exercise; 2 h post-exercise, and 6 h post-exercise for serum glucose and insulin. Blood variables were transformed to percent change values and analyzed by a 3 x 4 repeated measures MANOVA. Muscle biopsies were obtained at baseline, 30 min post-exercise, 2 h post-exercise and 6 h post-exercise for ERK1/2, IRS, Akt/PKB, GSK, mTOR, 4E-BP1, and P70S6K. Skeletal muscle variables were transformed to percent change values and analyzed by 3 x 4 repeated measures MANOVA. Univariate ANOVAs were utilized as follow-up tests to the MANOVA for select variables. Results: MANOVA results demonstrate a significant group x time interaction for insulin and glucose (P<.05). Despite a nearly 3 fold-increase of insulin over fasting baseline measures in the CHO groups as compared to the placebo group, neither BCAA + CHO or CHO significantly increased any of the muscle variables. Univariate analysis demonstrated significant group x time interaction for Akt/PKB phosphorylation (p=0.039) suggestive of a group effect. The following muscle variables demonstrated by MANOVA a significant time effect: IRS (p=.054); Akt/PKB (p=0.011); ERK1/2 (p=0.026); p70S6K (p=0.038). A time trend for mTOR (p=0.089) was noted. No significant effects were found for GSK and 4E-BP above baseline or among groups. Summary: The results indicate that RE but not BCAA + CHO or CHO increased the phosphorylation status of IRS, AKT/PKB, p70S6K and ERK above baseline levels (p<.05) with trends for group x time interaction for Akt/PKB and trend for mTOR activation. Phosphorylation of GSK and 4E-BP was not influenced by the RE and supplementation protocol.
DepartmentHealth, Human Performance and Recreation.
Showing items related by title, author, creator and subject.
Effects of a high protein diet on weight loss, markers of health, and functional capacity in senior-aged females participating in the Curves® fitness program. Galbreath, Melyn. (2008-12-01)Purpose: To determine the effectiveness of elderly females aged 60-75 years following the Curves fitness and weight loss program on body composition, markers of health, and functional capacity. Methods: 55 senior aged ...
Effects of four weeks of daily soy or dairy milk ingestion on the exercise-induced proteolytic responses in plasma and skeletal muscle in a post-menopausal female population. Serra, Monica Christine. (2009-08-25)Sarcopenia is defined as a loss of muscle mass and muscle strength associated with aging. Changes in muscle function can occur as early as the fourth decade of life. Evidence indicates that the calpain and ubiquitin ...
Effects of four weeks of daily soy milk or dairy milk ingestion on the exercise induced inflammatory and oxidative responses in plasma and skeletal muscle in a post-menopausal female population. Beavers, Kristen Marie. (2009-08-24)The process of senescence is associated with increasing inflammation and subsequent oxidative stress in the body, both of which can exert negative health effects at local and systemic levels. Attenuation of such processes ...