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Activation of mTORC1 by leucine is potentiated by branched chain amino acids and even more so by essential amino acids following resistance exercise
Marcus Moberg, William Apró, Bjorn Ekblom, Gerrit van Hall, Hans-Christer Holmberg, Eva Blomstrand
American Journal of Physiology - Cell Physiology Published 6 April 2016 Vol. no. , DOI: 10.1152/ajpcell.00374.2015
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Abstract
Protein synthesis is stimulated by resistance exercise and intake of amino acids, in particular leucine. Moreover, activation of mTORC1 signaling by leucine is potentiated by the presence of other essential amino acids (EAA). However, the contribution of the branched-chain amino acids (BCAA) to this effect is yet unknown. Here we compare the stimulatory role of leucine, BCAA and EAA ingestion on anabolic signaling following exercise. Accordingly, eight trained volunteers completed four sessions of resistance exercise during which they ingested either placebo, leucine, BCAA or EAA (including the BCAA) in random order. Muscle biopsies were taken at rest, immediately after exercise and following 90 and 180 min of recovery. Following 90 min of recovery the activity of S6K1 was greater than at rest in all four trials (Placebo<Leucine<BCAA<EAA; P<0.05 time x supplement), with a 9-fold increase in the EAA trial. At this same time-point phosphorylation of 4E-BP1 at Thr37/46 was unaffected by supplementation, while that of Thr46 alone exhibited a pattern similar to that of S6K1, being 18% higher with EAA than BCAA. However, after 180 min of recovery this difference between EAA and BCAA had disappeared, although with both these supplements the increases were still higher than with leucine (40%, P<0.05) and placebo (100%, P<0.05). In summary, EAA ingestion appears to stimulate translation initiation more effectively than the other supplements, although the results also suggest that this effect is primarily attributable to the BCAA.
Marcus Moberg, William Apró, Bjorn Ekblom, Gerrit van Hall, Hans-Christer Holmberg, Eva Blomstrand
American Journal of Physiology - Cell Physiology Published 6 April 2016 Vol. no. , DOI: 10.1152/ajpcell.00374.2015
ArticleInfo PDF
Abstract
Protein synthesis is stimulated by resistance exercise and intake of amino acids, in particular leucine. Moreover, activation of mTORC1 signaling by leucine is potentiated by the presence of other essential amino acids (EAA). However, the contribution of the branched-chain amino acids (BCAA) to this effect is yet unknown. Here we compare the stimulatory role of leucine, BCAA and EAA ingestion on anabolic signaling following exercise. Accordingly, eight trained volunteers completed four sessions of resistance exercise during which they ingested either placebo, leucine, BCAA or EAA (including the BCAA) in random order. Muscle biopsies were taken at rest, immediately after exercise and following 90 and 180 min of recovery. Following 90 min of recovery the activity of S6K1 was greater than at rest in all four trials (Placebo<Leucine<BCAA<EAA; P<0.05 time x supplement), with a 9-fold increase in the EAA trial. At this same time-point phosphorylation of 4E-BP1 at Thr37/46 was unaffected by supplementation, while that of Thr46 alone exhibited a pattern similar to that of S6K1, being 18% higher with EAA than BCAA. However, after 180 min of recovery this difference between EAA and BCAA had disappeared, although with both these supplements the increases were still higher than with leucine (40%, P<0.05) and placebo (100%, P<0.05). In summary, EAA ingestion appears to stimulate translation initiation more effectively than the other supplements, although the results also suggest that this effect is primarily attributable to the BCAA.
