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OpenTrials
Completed

NCT Number: NCT03952884

Skeletal Muscle Protein Synthetic Response to Amino Acid and Peptides

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.

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Key information

Conditions

Protein Metabolism

Age range

18 year–35 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Freer Hall

Urbana, Illinois, 61801, United States

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

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
  • Asthma
  • 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

Treatment and study plan

Resistance exercise

Behavioral

Prior to protein consumption participants will perform an acute bout of resistance exercise. They will warm up with two sets of 10 repetitions at 35-75% working load respectively, then perform four working sets of 10-12 repetitions at 65-70% of 1-RM. 1 min, 30 sec rest periods will be implemented between each set.

No Resistance Exercise

Behavioral

Participants allocated to this group will not perform exercise prior to the administration of the nutritional intervention. Participants will remain at rest throughout the trial.

Leucine

Dietary Supplement

Participants will be given 2g of leucine dissolved in 250mL of water. Drink will be consumed immediately after exercise or equivalent time point for non-exercise group.

Dileucine

Dietary Supplement

Participants will be given 2g of dileucine dissolved in 250mL of water. Drink will be consumed immediately after exercise or equivalent time point for non-exercise group.

Primary outcomes

  1. 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.

  2. 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.

  3. 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

  1. Phosphorylation of muscle anabolic signaling

    Time frame: Baseline, immediately after ingestion of leucine/leucine peptides, and 3 hours after ingestion of leucine/leucine peptides

    Phosphorylation of anabolic signaling pathways will be assessed in the fasted state and after the ingestion of the experimental interventions.

Sponsors and collaborators

Lead sponsor

University of Illinois at Urbana-Champaign

Other

Registry information

Important dates

Study start
2019
Primary completion
2019
Study completion
2019
First posted
May 16, 2019
Registry last updated
Sep 28, 2020

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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