Willoughby, Darryn Scott, 1963-La Bounty, Paul.Baylor University. Dept. of Health, Human Performance and Recreation.2007-12-032007-12-0320072007-12-03http://hdl.handle.net/2104/5069Includes bibliographical references (p. 145-152).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.ix, 152 p. : ill.160580 bytes522350 bytesapplication/pdfapplication/pdfen-USBaylor 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.Leucine -- Physiological effect.Branched chain amino acids -- Physiological effect.Isometric exercise.Dietary supplements -- Physiological effect.ThesisWorldwide access