Journal
JOURNAL OF NUTRITION
Volume 139, Issue 6, Pages 1103-1109Publisher
AMER SOC NUTRITIONAL SCIENCE
DOI: 10.3945/jn.108.103853
Keywords
-
Categories
Funding
- National Dairy Council/DMI
- Illinois Department of Agriculture (CFAR)
- Egg Nutrition Center
Ask authors/readers for more resources
This study examined the impact of leucine (Leu) derived from complete meals on stimulation of skeletal muscle protein synthesis (MPS). Expt. 1 examined time course changes in translation initiation and MPS after a meal. Male rats (similar to 300 g) were trained for 5 d to eat 3 meals/d providing 20, 50, and 30% of energy from whey protein, carbohydrates, and fats, respectively. Plasma and skeletal muscle were collected at time 0 (baseline) after 12 h of food deprivation and then at 45, 90, 135, 180, and 300 min after a 4-g meal. Plasma Leu increased at 45 min and remained elevated through 180 min. MPS peaked at 45-90 min and returned to baseline by 180 min. Plasma Leu correlated with phosphorylation of ribosomal protein p70 S6 kinase (r = 0.723; P < 0.05), eukaryotic initiation factor 4E binding protein-1 (r = 0.773; P < 0.05), and MPS (r = 0.608; P < 0.05) overtime. Expt. 2 examined 3 levels of protein intake (10, 20, and 30% of energy) from 2 sources (wheat and whey) with different Leu contents (similar to 6.8 and similar to 10.9%, respectively) on stimulation of initiation and MPS. Rats were trained to eat 3 meals/d providing 14, 56, and 30% of energy from protein, carbohydrates, and fats. On d 6, MPS was evaluated at 90 min after rats consumed I of the 6 test meals. Whey protein stimulated initiation and MPS more than wheat and the differential response related to greater plasma Leu responses in the whey groups. These studies demonstrate that peak activation but not duration of MPS is proportional to the Leu content of a meal. J. Nutr. 139: 1103-1109, 2009.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available