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The effects of heavy resistance exercise in combination with orally administered branched-chain amino acids or leucine on insulin signaling and Akt/mTOR pathway activity in active males.

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dc.contributor.advisor Willoughby, Darryn Scott, 1963-
dc.contributor.author La Bounty, Paul.
dc.contributor.other Baylor University. Dept. of Health, Human Performance and Recreation. en
dc.date.copyright 2007
dc.identifier.uri http://hdl.handle.net/2104/5069
dc.description.abstract Purpose: To determine if activity of the insulin signaling pathway is increased during lower body resistance exercise due to supplemental BCAA or leucine ingestion. Methods: 30 recreationally trained males (22.5yrs; 81.1kg) were randomly assigned to 1 of 3 groups: Leucine (60mg/kg/bw), BCAA (120mg/kg/bw), or non-caloric placebo. Participants performed 4 sets of leg press and leg extension at 80% 1RM to failure (at least 8 reps). Supplements were ingested at 3 time points: 30 minutes prior to RE, and immediately pre- and post-RE. Venous blood was sampled at baseline (Pre); immediate pre- and post-exercise, 30 minutes post-exercise; 2hours post-exercise, and 6 hours post-exercise for serum glucose, insulin, GH, and IGF-1. Muscle biopsies were obtained at baseline, and 30 minutes post, and 2 and 6 hours post-exercise for IRS-1, Akt, mTOR, 4E-BP1, and P70-S6K. Skeletal muscle variables were transformed to delta values and analyzed using a 3 (group) x 4 (time points) repeated measures MANOVA. Univariate ANOVAs (Bonferroni adjusted) were utilized as follow-up tests to the MANOVA. Post-hoc tests of the interaction effects demonstrated in the ANOVA were analyzed using independent samples T-tests. Results: Neither BCAA or leucine significantly increased any of the 4 serum variables. A group x time interaction for IRS-1 phosphorylation demonstrated that the leucine group was significantly elevated at 2hr post and 6hr post when compared to the BCAA group (p < .05). A group x time interaction for 4E-BP1 phosphorylation demonstrated that the leucine and BCAA groups were both elevated at the 2hr post in comparison with the placebo (p < .05). BCAA was significantly greater than leucine at 6 hours (p < .05) as well. No interactions were observed for Akt, mTOR, or P70-S6K. Summary: The results indicate that BCAA and leucine supplementation with RE increased the phosphorylation status of 4E-BP1 at 2 hours post-exercise and the BCAA group increased the phosphorylation of 4E-BP1 greater than leucine (p < .05) at 6 hours post-exercise. 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 librarywebmaster@baylor.edu for inquiries about permission. en
dc.subject Leucine -- Physiological effect. en
dc.subject Branched chain amino acids -- Physiological effect. en
dc.subject Isometric exercise. en
dc.subject Dietary supplements -- Physiological effect. en
dc.title The effects of heavy resistance exercise in combination with orally administered branched-chain amino acids or leucine on insulin signaling and Akt/mTOR pathway activity in active males. en
dc.type Thesis en
dc.description.degree Ph.D. en
dc.rights.accessrights Worldwide access en
dc.contributor.department Health, Human Performance and Recreation. en


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