Willoughby, Darryn Scott, 1963-Campbell, Bill.Baylor University. Dept. of Health, Human Performance and Recreation.2007-12-032007-12-0320072007-12-03http://hdl.handle.net/2104/5048Includes bibliographical references (p. 134-146).Purpose: To determine if leucine or BCAA ingestion increases the activation of the ERK1/2 MAPK pathway greater than that which resistance exercise (RE) elicits alone; to determine a possible mechanism for a BCAA or leucine induced ERK1/2 MAPK pathway via IRS-1 and SHP-2. Methods: 30 males (22.5yrs; 81.1kg) were randomly assigned to 1 of 3 groups: Leucine (60mg/kg/bw), BCAA (120mg/kg/bw), or placebo. 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 post-exercise, 30min post-exercise; 2hrs post-exercise, and 6hrs post-exercise for serum glucose, insulin, GH, and IGF-1. Muscle biopsies were sampled at baseline, and 30min post, 2hr post, and 6hr post-exercise for MEK1, ERK1/2, IRS-1, and SHP-2. Skeletal muscle variables were transformed to delta values and analyzed via a 3 (group) x 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 samples T-test. Results: Neither BCAA or leucine increased the secretion of the 4 serum variables. A group x time interaction relative to ERK1/2 activation indicated that the BCAA group was significantly elevated at the 2hr post and 6hr post time points in comparison with the Leucine (p < .05) and Placebo groups (p < .001). A group x time interaction for IRS-1 activation indicated that the Leucine group was significantly elevated at 2hr post and 6hr post in comparison with the BCAA (p < .05) group. No group x time interactions were observed for MEK1 or SHP-2. Summary: BCAA supplementation increased the phosphorylation status of ERK1/2 in conjunction with RE at 2 and 6 hours post-exercise. Leucine supplementation did not have any effect on ERK1/2 activation.x, 146 p. : ill.506952 bytes147647 bytesapplication/pdfapplication/pdfenBaylor 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.Branched chain amino acids -- Physiological effect.Leucine -- Physiological effect.Isometric exercise.Dietary supplements -- Physiological effect.ThesisWorldwide access