Time Course of Postprandial Protein Metabolism

Study Overview
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Brief Summary
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The anabolic action of 'fast' whey protein on the regulation of postprandial muscle protein synthesis has been established to be short-lived in healthy young adults. Our aim was assess the time course of anabolic signaling events and stimulation of muscle protein synthesis rates (MPS) after ingestion of a food source that represents a more typical meal-induced pattern of aminoacidemia, namely milk protein concentrate, in healthy young males.

Official Title
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Time-dependent Regulation of Postprandial Muscle Protein Synthesis After Milk Protein Ingestion in Young Men

Conditions
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Muscle Protein Synthesis, Protein Metabolism

Intervention / Treatment
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* Dietary Supplement: Milk Protein Concentrate


Participation Criteria
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Eligibility Criteria
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Inclusion criteria Males Aged between 18-35 years Healthy, recreationally active BMI < 30 kg/m2 Exclusion criteria Smoking Allergies to milk proteins Vegetarians Diagnosed GI tract diseases Female Arthritic conditions A history of neuromuscular problems Previous 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).

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 35 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Milk Protein Concentrate<br>Seven young men (age: 22±1 y) will undergo repeated blood and biopsy sampling during primed continuous L-[ring-2H5]phenylalanine and L-[1-13C]leucine tracer infusions, and ingested 38 g of L-[1-13C]phenylalanine- and L-[1-13C]leucine-labeled milk protein concentrate | Dietary Supplement: Milk Protein Concentrate<br>* The macronutrient composition and energy of the milk protein beverage provided to participants is 38 g protein (3.46 g leucine), 4.17 g carbohydrate, and 1.4 g fat. The milk protein met all chemical and bacteriologic specifications for human consumption. The L-[1-13C]phenylalanine and L-[1-13C]leucine enrichments in the milk protein concentrate averaged 38.3 and 10.8 mole percent excess (MPE), respectively.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Fractional synthesis rates of myofibrillar protein | Myofibrillar protein synthesis rates will be assessed during the postabsorptive period for 3 hours, and every 1-2 hours during the 5 hours after protein ingestion. This will allow us assess the timecourse of muscle protein synthesis after eating. | 8 hours | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Phosphorylation of muscle anabolic signaling | Phosphorylation of anabolic signaling pathways (mTORC1, AKT, and P70S6K) involved in the stimulation of myofibrillar protein synthesis rates will be assessed during the postabsorptive period for 3 hours, and every 1-2 hours during the 5 hours after protein ingestion. | 8 hours | 
| Exogenous rate of phenylalanine appearance | Dietary derived phenylalanine availability will be measured during the 5 h postprandial phase to determine its relationship with the fractional synthesis rates of myofibrillar protein and phosphorylation of muscle anabolic signaling | 5 hours | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Protein, Amino Acids, Anabolic Signaling, Muscle Mass