Protein distribution affects muscle mass based on differences in postprandial muscle protein synthesis and plasma leucine in rats

Methods Male Sprague Dawley rats (275g) were fed isocaloric/isonitrogenous meals containing whey protein, with protein either distributed evenly at 16% of total energy over 3 meals (ED-Whey) or unevenly distributed over 3 meals (UD-Whey) with the first 2 meals containing only 8% of energy from whey protein and only the dinner meal containing sufficient protein to optimize muscle protein synthesis (MPS) (27.5% of total energy from whey protein) for 11 weeks. Measurements were taken to assess postprandial rates of MPS, plasma amino acids, mammalian target of rapamycin (mTOR) signaling, and the animals’ body composition was assessed by Dual energy X-ray absorptiometry (DXA). Hind limb muscle weights were taken to asses differences in muscle mass.