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Enriching a bolus protein drink with a small amount of crystalline tracer (4% enrichment) does not disrupt isotopic steady-state conditions in plasma or intracellular precursor pools.

For researchers using stable isotopes to measure muscle protein synthesis, you can enrich your protein drink with a small amount of tracer (e.g., 4% enrichment) without disrupting the steady-state conditions in your precursor pools. This allows for accurate measurement of muscle protein synthesis after a bolus protein feeding, even following exercise.

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We also found that adding a modest amount of tracer (4% enriched), calculated based on the measured phenylalanine content of the protein (3.5%) in the drink, did not compromise steady-state conditions (slope of the enrichment curve not different from zero) in the plasma free or, more importantly, the IC pool (both P > 0.05).
Nicholas A. Burd et al. · Nutrition & Metabolism · 2011

Why this rating

Validated in Study 2 with n=8, showing stable slopes in enrichment curves (P>0.05).

Source

Validation of a single biopsy approach and bolus protein feeding to determine myofibrillar protein synthesis in stable isotope tracer studies in humans

Nicholas A. Burd et al. · Nutrition & Metabolism · 2011

DOI 10.1186/1743-7075-8-15

rct · n=16Cited 65×
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DOI resolved against Crossref · corpus check 2026-06-10

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