Co-ingestion of carbohydrate with branched-chain amino acids or L-leucine does not preferentially increase serum IGF-1 and expression of myogenic-related genes in response to a single bout of resistance exercise.
The purpose of this study was to determine if the co-ingestion of carbohydrate (CHO) with branched-chain amino acids (BCAA) or L-leucine (LEU) preferentially affected serum IGF-1 and the expression of myogenic-related genes in response to resistance exercise (RE). Forty-one college-age males were randomly assigned to 1 of 4 groups: CHO, CHO-BCAA, CHO-LEU, or placebo (PLC). Resistance exercise consisted of 4 sets of 10 repetitions of leg press and leg extension at 80 % 1RM. Supplements were ingested peri-exercise, and venous blood and muscle biopsies were obtained pre-exercise (PRE), and at 30, 120, and 360 min post-exercise. Serum IGF-1 was determined with ELISA, and skeletal muscle mRNA expression of myostatin, ACTRIIB, p21kip, p27kip, CDK2, cyclin B1, cyclin D1, Myo-D, myogenin, MRF-4, and myf5 was determined using real-time PCR. Results were analyzed by two-way ANOVA for serum IGF-1 and two-way MANOVA for mRNA expression. Serum IGF-1 in CHO + BCAA was greater than PLC (p < 0.05) but was not affected by RE (p > 0.05). A significant group × time interaction was located for cylin D1 (p < 0.05), but not for any other genes. However, significant time effects were noted for cyclin B1 and p21cip (p < 0.05). At 30, 120 and 360 min post-exercise, p21cip was significantly less than PRE. Cyclin D1 was greater than PRE and 30 min post-exercise at 120 and 360 min post-exercise, whereas cyclin B1 was significantly greater than PRE at 120 min post-exercise (p < 0.05). Unlike the co-ingestion of CHO with either BCAA or L-leucine in conjunction with RE, the expression of various myogenically related genes were up-regulated with RE.
Department of Health Sciences, Northeastern University, Boston, MA, 02115, USA, r.li@neu.edu.
Rui
R
Li
Maria P
MP
Ferreira
Matthew B
MB
Cooke
Paul
P
La Bounty
Bill
B
Campbell
Mike
M
Greenwood
Darryn S
DS
Willoughby
Richard B
RB
Kreider
D000293:Adolescent; D000328:Adult; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D005786:Gene Expression Regulation / Q000187:drug effects* / Q000502:physiology; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000096:biosynthesis*; D007930:Leucine / Q000008:administration & dosage*; D008297:Male; D009124:Muscle Proteins / Q000096:biosynthesis*; D010807:Physical Endurance / Q000187:drug effects* / Q000502:physiology
D004040:Dietary Carbohydrates; C583557:IGF1 protein, human; D009124:Muscle Proteins; D007334:Insulin-Like Growth Factor I; D007930:Leucine