F-34 Thematic Poster - Protein Metabolism Friday, May 31, 2019, 3: 15 PM - 5: 15 PM Room: CC-102A
Leucine Co-Ingestion Augments the Muscle Protein Synthetic Response to the Ingestion of 15 g Protein During Recovery from Resistance Exercise in Older Men
2874 Board #4 May 31 3:15 PM - 5:15 PM
PURPOSE: Older adults have shown an attenuated post-exercise increase in muscle protein synthesis rates following ingestion of smaller amounts of protein when compared to younger adults. Consequently, more protein may be required to increase post-exercise muscle protein synthesis rates in older as compared to younger men. The present study investigated whether co-ingestion of 1.5 g free leucine with a single, 15 g bolus of protein augments the muscle protein synthetic response during recovery from resistance-type exercise in older men.
METHODS: Twenty-four healthy older men (67±1 y) were randomly assigned to ingest 15 g milk protein concentrate (MPC80) with (15G+LEU; n=12) or without (15G; n=12) 1.5 g free leucine after performing a single bout of resistance-type exercise. Post-prandial protein digestion and amino acid absorption kinetics, whole body protein metabolism, and post-prandial myofibrillar protein synthesis rates were assessed using primed, continuous infusions with L-[ring-2H5]-phenylalanine, L-[ring-2H2]-tyrosine and L-[1-13C]-leucine combined with the ingestion of intrinsically L-[1-13C]-phenylalanine labeled milk protein.
RESULTS: A total of 70±1% (10.5±0.2 g) and 75±2% (11.2±0.3 g) of the protein-derived amino acids were released in the circulation during the 6-h post-exercise recovery phase in 15G+LEU and 15G, respectively (P<0.05). Post-exercise myofibrillar protein synthesis rates were 16% (0.058±0.003 vs 0.049±0.002 %·h-1; P<0.05; based upon L-[ring-2H5]-phenylalanine) and 19% (0.071±0.003 vs 0.060±0.003 %·h-1, P<0.05; based upon L-[1-13C]-leucine) greater in 15G+LEU when compared with 15G.
CONCLUSIONS: Leucine co-ingestion augments the post-exercise muscle protein synthetic response to the ingestion of a single 15 g bolus of protein in older men.Copyright © 2019 by the American College of Sports Medicine