Effects of ingesting branched chain amino acids and carbohydrate on myostatin signaling and markers of myogenesis in response to a bout of heavy resistance exercise.

DSpace/Manakin Repository

BEARdocs is currently undergoing a scheduled upgrade. We expect the upgrade to be completed no later than Monday, March 2nd, 2015. During this time you will be able to access existing documents, but will not be able to log in or submit new documents.

Show simple item record

dc.contributor.advisor Kreider, Richard B., 1962-
dc.contributor.advisor Willoughby, Darryn Scott, 1963- Li, Rui, 1972-
dc.contributor.other Baylor University. Dept. of Health, Human Performance and Recreation. en 2008-08
dc.description.abstract Purpose: To determine if co-ingestion of carbohydrate (CHO) with branchedchain amino acids (BCAA) or leucine (Leu) downregulates the myostatin signaling pathway and upregulates the makers of myogenesis to a extent greater than that which resistance exercise elicits alone; to explore a possible mechanism for a CHO-BCAA or CHO-Leu induced the modification of myostatin pathway and the activation of myogenesis. Methods: 31 males (22.5yrs; 81.1kg) were randomly assigned to 1 of 3 groups: CHO-BCAA (maltodextrin 1.5 g/kg/bw, BCAA 120mg/kg/bw), CHO-Leucine (maltodextrin 1.5 g/kg/bw, Leu 60mg/kg/bw) and CHO alone (maltodextrin 1.5 g/kg/bw). A control group ingesting placebo (450 ml Crystal Light®) was employed from the previous study using the same study design in the same lab. Subjects performed 4 sets of leg press and leg extension at 80% 1RM to failure. Supplementation was ingested at 3 time points: 30 minutes prior to RE, and immediately pre- and post-RE. Venous blood was sampled at baseline; 30min later, immediate postexercise, 30min post-exercise; 2hr post-exercise, and 6hr post-exercise for serum glucose, insulin, IGF-1, myostatin, myostatin propeptide, follistatin and FLRG. Muscle biopsies were sampled at baseline, and 30min post, 2hr post, and 6hr post-exercise for myostatin, ActRIIB, p21cip, p27kip, myoD, myf-5, myogenin and MRF-4 mRNA expression. Serum variables were expressed in delta values as percent change and analyzed via a 4 (group) × 6 (time points) repeated measures MANOVA. Muscle variables were analyzed as CT ratio for relative mRNA expression via a 4 (group) × 4 (time points) repeated measures MANOVA. Univariate ANOVAs (Bonferroni adjusted) were conducted as follow-up tests to the MANOVA. Post-hoc tests of the interaction effects demonstrated in the ANOVA were investigated via an independent sample T-test. Results: CHO-BCAA, CHO-Leu and CHO alone significantly increased blood glucose and serum insulin levels combined with resistance exercise. Either CHO-BCAA or CHO-Leu enhanced serum insulin to a greater extent compared with CHO alone, nonetheless no statistically significance indicated. None of the CHO-BCAA, CHO-Leu or CHO alone, compared with placebo, modified serum IGF-1, myostatin and its inhibitors. Regarding muscle samples, a univariate group × time interaction relative to myogenin mRNA expression indicated that the CHO-Leu group was significantly upregulated at the 6hr post time point in comparison with the Placebo group (p < .05). No group × time interactions were observed for the myostain signaling molecules and other myogenic regulatory factors except myogenin. Summary: CHO-Leu supplementation upregulated the myogenin mRNA expression in conjunction with resistance exercise at 6hr post-exercise. Co-ingestion of BCAA or Leu had no effect on the inhibition of myostatin signaling at pre- and post-translational level. en
dc.rights Baylor University theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. Contact for inquiries about permission. en
dc.subject Branched chain amino acids -- Physiological effect. en
dc.subject Leucine -- Physiological effect. en
dc.subject Carbohydrates -- Physiological effect. en
dc.subject Isometric exercise -- Physiological aspects. en
dc.subject Myogenesis -- Analysis. en
dc.subject Muscle proteins -- Analysis. en
dc.title Effects of ingesting branched chain amino acids and carbohydrate on myostatin signaling and markers of myogenesis in response to a bout of heavy resistance exercise. en
dc.type Thesis en Ph.D. en
dc.rights.accessrights Baylor University access only en
dc.contributor.department Health, Human Performance and Recreation. en

Files in this item

This item appears in the following Collection(s)

Show simple item record

Search BEARdocs

Advanced Search


My Account