Skeletal Muscle Protein Synthetic Response to Amino Acid and Peptides
Trial Snapshot
- Phase
- Not Applicable
- Status
- Completed
- Enrollment
- 10
- Locations
- 1
- Primary Endpoint
- Fractional Synthetic Rate of Myofibrillar Proteins
Study Overview
Brief Summary
Skeletal muscle quality is an important determinant of exercise performance and overall health. It is vital for not just movement, but also metabolizing nutrients. Protein from the diet can promote muscle protein synthesis for muscle recovery and growth. More importantly, doing so shifts net protein balance positively (e.g. protein synthesis is greater than protein breakdown) and promotes greater rates of muscle protein turnover. Leucine is an amino acid required to build muscle, but it also acts as a signaling molecule informing the muscle to start protein synthesis. Before reaching skeletal muscle, dietary protein is digested into small peptides and free amino acids. Rate of absorption from the intestine to the blood stream is significantly faster for peptides compared to amino acids. As amino acid availability in the blood is a precursor for muscle protein synthesis, our objective is to determine if the different absorption rates between free amino acid and peptides influence muscle protein synthetic and breakdown rates.
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Crossover
- Primary Purpose
- Basic Science
- Masking
- Triple (Participant, Investigator, Outcomes Assessor)
Eligibility Criteria
- Ages
- 18 Years to 35 Years (Adult)
- Sex
- All
- Accepts Healthy Volunteers
- Yes
Inclusion Criteria
- •Recreationally-active adults: ≥ 30 min of physical activity at moderate intensity ≥ 3 times per week
- •Ages: 18-35 years old
- •English fluency
Exclusion Criteria
- •Tobacco, nicotine (patch/gum) use (previous 6 mo)
- •Alcohol consumption >10 drinks per week
- •Metabolic disorders (e.g., Metabolic Syndrome, Diabetes, thyroid diseases)
- •Cardiovascular disease, arrhythmias
- •Hypogonadism
- •History of uncontrolled hypertension
- •Orthopedic injury/surgery (within 1 yr)
- •Hepatorenal, musculoskeletal, autoimmune, or neurological disease
- •History of neuromuscular problems
- •Previous participation in amino acid tracer studies
- •Predisposition to hypertrophic scarring or keloid formation
- •Consumption of ergogenic-levels of dietary supplements that may affect muscle mass (e.g., creatine, HMB), insulin-like substances, or anabolic/catabolic pro-hormones (e.g., DHEA) within 6 weeks prior to participation
- •Consumption of thyroid, androgenic, or other medications known to affect endocrine function
- •Consumption of medications known to affect protein metabolism (e.g., prescription-strength corticosteroids, non-steroidal anti-inflammatories, or acne medication)
- •Currently pregnant
Arms & Interventions
Leucine
Participants will be allocated to an exercise or non-exercise group. After resistance exercise (or equivalent time point for non-exercise group), participants will consume 2g leucine powder dissolved in 250 mL of water.
Intervention: Resistance Exercise (Behavioral)
Leucine
Participants will be allocated to an exercise or non-exercise group. After resistance exercise (or equivalent time point for non-exercise group), participants will consume 2g leucine powder dissolved in 250 mL of water.
Intervention: No Resistance Exercise (Behavioral)
Leucine Peptide (Dileucine)
Participants will be allocated to an exercise or non-exercise group. After resistance exercise (or equivalent time point for non-exercise group), participants will consume 2g protein peptide powder dissolved in 250 mL of water.
Intervention: Resistance Exercise (Behavioral)
Leucine Peptide (Dileucine)
Participants will be allocated to an exercise or non-exercise group. After resistance exercise (or equivalent time point for non-exercise group), participants will consume 2g protein peptide powder dissolved in 250 mL of water.
Intervention: No Resistance Exercise (Behavioral)
Leucine Peptide (Dileucine)
Participants will be allocated to an exercise or non-exercise group. After resistance exercise (or equivalent time point for non-exercise group), participants will consume 2g protein peptide powder dissolved in 250 mL of water.
Intervention: Dileucine (Dietary Supplement)
Leucine
Participants will be allocated to an exercise or non-exercise group. After resistance exercise (or equivalent time point for non-exercise group), participants will consume 2g leucine powder dissolved in 250 mL of water.
Intervention: Leucine (Dietary Supplement)
Outcomes
Primary Outcomes
Fractional Synthetic Rate of Myofibrillar Proteins
Time Frame: Postabsorptive for 3.5 hours, Postprandial for 3 hours.
Myofibrillar muscle protein synthesis rates will be assessed during the 3.5hr Postabsorptive period (e.g. non-fed state) and the 3hr postprandial period (e.g. fed state) for both experimental interventions (e.g. leucine and leucine peptide). This will allow us to assess the change in fractional synthetic rate from the Postabsorptive period to the postprandial period.
Fractional Synthetic Rate of Mixed Muscle Proteins
Time Frame: Postabsorptive for 3.5 hours, Postprandial for 3 hours.
Mixed muscle protein synthesis rates will be assessed during the 3.5hr Postabsorptive period (e.g. non-fed state) and the 3hr postprandial period (e.g. fed state) for both experimental interventions (e.g. leucine and leucine peptide). This will allow us to assess the change in fractional synthetic rate from the Postabsorptive period to the postprandial period.
Fractional Breakdown Rate of Mixed Muscle Proteins
Time Frame: Postprandial for 1 hour
Mixed muscle protein breakdown rates will be assessed during the first hour of the postprandial period (e.g. fed state) for both experimental interventions (e.g. leucine and leucine peptide). This will allow us to assess the change in fractional breakdown rate for each respective experimental intervention.
Secondary Outcomes
- Phosphorylation of muscle anabolic signaling(Baseline, immediately after ingestion of leucine/leucine peptides, and 3 hours after ingestion of leucine/leucine peptides)
Investigators
Nicholas Burd
Assistant Professor
University of Illinois at Urbana-Champaign