Muscle Protein Synthesis After Whole Egg vs. Egg White Consumption

On both infusion trials, participants will report to the laboratory at 0700 h after an overnight fast. Upon arrival to the lab, a baseline breath sample will be collected for determination of 13CO2 enrichment by isotope ratio mass spectrometry. A Teflon catheter will be inserted into an antecubital vein for baseline blood sample collection (t=-210 min) and then participants will receive priming doses of NaH13CO2 (2.35 µmol·kg-1), L-[1-13C]leucine (7.6 µmol·kg-1), and L-[ring-2H5]phenylalanine (2.0 µmol·kg-1). Subsequently, a continuous intravenous infusion of L-[1-13C]leucine (0.10 µmol·kg-1·min-1) and L-[ring-2H5]phenylalanine (0.05 µmol·kg-1·min-1) will be initiated (t=-210 min) and maintained over the infusion trials. A second Teflon catheter willinserted into a heated dorsal hand vein for repeated arterialized blood sampling and remained patent by a 0.9% saline drip. Breath samples and arterialized blood samples and will be collected every 30 or 60 min during the postabsorptive- and postprandial states. In the post-absorptive state of infusion trial 1, muscle biopsies will be collected at t=-150 and -30 min of infusion to determine basal-state myofibrillar protein synthesis rates, relative skeletal muscle amino acid transporter content, and anabolic-related signaling. In the subsequent cross-over trial only 1 muscle biopsy will be collected at t=-30 for Western blot analysis and postabsorptive myofibrillar protein-bound tracer enrichment. After collection of the resting muscle biopsy at t=-30 for both trials, the participants will perform resistance exercise that consists of 4 sets of 10 repetitions at 80% of 10-RM for both leg press and leg extension exercise.

Immediately after completion of the exercise bout, participants will consume 3 whole eggs or an equivalent amount of protein from egg whites (t=0 min). Completion of the meal will mark the start of the postprandial phase (t=0 min) and additional muscle biopsies will be collected at t=120 and 300 min.

Inclusion criteria

• Male
• Aged 18-35 years
• Healthy, active (self-reported to exercise 2 - 4 times per week)
• BMI > 18.5 and < 25 kg/m2

Exclusion criteria

• Smoking
• Known allergies to egg consumption
• Vegans
• Diagnosed GI tract diseases
• Arthritic conditions
• A history of neuromuscular problems
• Diagnosed cognitive impairments
• Recent (1 year) participation in amino acid tracer studies
• Predisposition to hypertrophic scarring or keloid formation
• Individuals on any medications known to affect protein metabolism (i.e. corticosteroids, non-steroidal anti-inflammatories, or prescription strength acne medications).
• High blood pressure (Systolic > 140 mm HG; Diastolic > 90 mm HG)