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Leucine or carbohydrate supplementation reduces AMPK and eEF2 phosphorylation and extends postprandial muscle protein synthesis in rats

Leucine or carbohydrate supplementation reduces AMPK and eEF2 phosphorylation and extends postprandial muscle protein synthesis in rats
Leucine or carbohydrate supplementation reduces AMPK and eEF2 phosphorylation and extends postprandial muscle protein synthesis in rats
Muscle protein synthesis (MPS) increases after consumption of a protein-containing meal but returns to baseline values within 3 h despite continued elevations of plasma amino acids and mammalian target of rapamycin (mTORC1) signaling. This study evaluated the potential for supplemental leucine (Leu), carbohydrates (CHO), or both to prolong elevated MPS after a meal. Male Sprague-Dawley rats (?270 g) trained to consume three meals daily were food deprived for 12 h, and then blood and gastrocnemius muscle were collected 0, 90, or 180 min after a standard 4-g test meal (20% whey protein). At 135 min postmeal, rats were orally administered 2.63 g of CHO, 270 mg of Leu, both, or water (sham control). Following test meal consumption, MPS peaked at 90 min and then returned to basal (time 0) rates at 180 min, although ribosomal protein S6 kinase and eIF4E-binding protein-1 phosphorylation remained elevated. In contrast, rats administered Leu and/or CHO supplements at 135 min postmeal maintained peak MPS through 180 min. MPS was inversely associated with the phosphorylation states of translation elongation factor 2, the "cellular energy sensor" adenosine monophosphate-activated protein kinase-? (AMPK?) and its substrate acetyl-CoA carboxylase, and increases in the ratio of AMP/ATP. We conclude that the incongruity between MPS and mTORC1 at 180 min reflects a block in translation elongation due to reduced cellular energy. Administering Leu or CHO supplements ?2 h after a meal maintains cellular energy status and extends the postprandial duration of MPS.
eukaryotic elongation factor 2, adenosine 5?-monophosphate-activated protein kinase, translation initiation, translation elongation, branched-chain amino acids, whey protein, mammalian target of rapamycin complex 1
0193-1849
E1236-E1242
Wilson, Gabriel J.
fe4aec61-a6e6-4859-b067-a6044ec5cc16
Layman, Donald K.
3dcf2af0-c84f-4ffc-a8ce-b61b08acd160
Moulton, Christopher J.
d70b54ea-5e37-4b56-9858-de90a654b45a
Norton, Layne E.
722d4d5a-6643-4002-bf93-4be3bd624301
Anthony, Tracy G.
b8517c41-9597-4145-b2ea-1b5e1f4f1057
Proud, Christopher G.
59dabfc8-4b44-4be8-a17f-578a58550cb3
Rupassara, S. Indu
944c3719-6a2d-4571-be6c-762191bf7ac8
Garlick, Peter J.
ad1fbcea-9588-4879-bd0d-e6f723a636b6
Wilson, Gabriel J.
fe4aec61-a6e6-4859-b067-a6044ec5cc16
Layman, Donald K.
3dcf2af0-c84f-4ffc-a8ce-b61b08acd160
Moulton, Christopher J.
d70b54ea-5e37-4b56-9858-de90a654b45a
Norton, Layne E.
722d4d5a-6643-4002-bf93-4be3bd624301
Anthony, Tracy G.
b8517c41-9597-4145-b2ea-1b5e1f4f1057
Proud, Christopher G.
59dabfc8-4b44-4be8-a17f-578a58550cb3
Rupassara, S. Indu
944c3719-6a2d-4571-be6c-762191bf7ac8
Garlick, Peter J.
ad1fbcea-9588-4879-bd0d-e6f723a636b6

Wilson, Gabriel J., Layman, Donald K., Moulton, Christopher J., Norton, Layne E., Anthony, Tracy G., Proud, Christopher G., Rupassara, S. Indu and Garlick, Peter J. (2011) Leucine or carbohydrate supplementation reduces AMPK and eEF2 phosphorylation and extends postprandial muscle protein synthesis in rats. American Journal of Physiology: Endocrinology and Metabolism, 301 (6), E1236-E1242. (doi:10.1152/ajpendo.00242.2011). (PMID:21917636)

Record type: Article

Abstract

Muscle protein synthesis (MPS) increases after consumption of a protein-containing meal but returns to baseline values within 3 h despite continued elevations of plasma amino acids and mammalian target of rapamycin (mTORC1) signaling. This study evaluated the potential for supplemental leucine (Leu), carbohydrates (CHO), or both to prolong elevated MPS after a meal. Male Sprague-Dawley rats (?270 g) trained to consume three meals daily were food deprived for 12 h, and then blood and gastrocnemius muscle were collected 0, 90, or 180 min after a standard 4-g test meal (20% whey protein). At 135 min postmeal, rats were orally administered 2.63 g of CHO, 270 mg of Leu, both, or water (sham control). Following test meal consumption, MPS peaked at 90 min and then returned to basal (time 0) rates at 180 min, although ribosomal protein S6 kinase and eIF4E-binding protein-1 phosphorylation remained elevated. In contrast, rats administered Leu and/or CHO supplements at 135 min postmeal maintained peak MPS through 180 min. MPS was inversely associated with the phosphorylation states of translation elongation factor 2, the "cellular energy sensor" adenosine monophosphate-activated protein kinase-? (AMPK?) and its substrate acetyl-CoA carboxylase, and increases in the ratio of AMP/ATP. We conclude that the incongruity between MPS and mTORC1 at 180 min reflects a block in translation elongation due to reduced cellular energy. Administering Leu or CHO supplements ?2 h after a meal maintains cellular energy status and extends the postprandial duration of MPS.

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e-pub ahead of print date: 13 September 2011
Published date: 1 December 2011
Keywords: eukaryotic elongation factor 2, adenosine 5?-monophosphate-activated protein kinase, translation initiation, translation elongation, branched-chain amino acids, whey protein, mammalian target of rapamycin complex 1
Organisations: Centre for Biological Sciences

Identifiers

Local EPrints ID: 350238
URI: http://eprints.soton.ac.uk/id/eprint/350238
ISSN: 0193-1849
PURE UUID: 2e2ffa6f-a0c4-463c-961a-af5e8b6a708b

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Date deposited: 20 Mar 2013 12:04
Last modified: 16 Jul 2019 21:40

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Contributors

Author: Gabriel J. Wilson
Author: Donald K. Layman
Author: Christopher J. Moulton
Author: Layne E. Norton
Author: Tracy G. Anthony
Author: Christopher G. Proud
Author: S. Indu Rupassara
Author: Peter J. Garlick

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