The Effect of Carbohydrate Ingestion Following Eccentric Resistance Exercise on AKT/mTOR and ERK Pathways: A Randomized, Double-Blinded, Crossover Study

Journal article


Figueiredo, Vandre C., Farnfield, Michelle M., Ross, Megan L. R., Gran, Petra, Halson, Shona L., Peake, Jonathan M., Cameron-Smith, David and Markworth, James F.. (2019). The Effect of Carbohydrate Ingestion Following Eccentric Resistance Exercise on AKT/mTOR and ERK Pathways: A Randomized, Double-Blinded, Crossover Study. International Journal of Sport Nutrition and Exercise Metabolism. 29(6), pp. 664 - 670. https://doi.org/10.1123/ijsnem.2019-0075
AuthorsFigueiredo, Vandre C., Farnfield, Michelle M., Ross, Megan L. R., Gran, Petra, Halson, Shona L., Peake, Jonathan M., Cameron-Smith, David and Markworth, James F.
Abstract

Purpose: To determine the acute effects of carbohydrate (CHO) ingestion following a bout of maximal eccentric resistance exercise on key anabolic kinases of mammalian target of rapamycin and extracellular signal-regulated kinase (ERK) pathways. The authors’ hypothesis was that the activation of anabolic signaling pathways known to be upregulated by resistance exercise would be further stimulated by the physiological hyperinsulinemia resulting from CHO supplementation. Methods: Ten resistance-trained men were randomized in a crossover, double-blind, placebo (PLA)-controlled manner to ingest either a noncaloric PLA or 3 g/kg of CHO beverage throughout recovery from resistance exercise. Muscle biopsies were collected at rest, immediately after a single bout of intense lower body resistance exercise, and after 3 hr of recovery. Results: CHO ingestion elevated plasma glucose and insulin concentrations throughout recovery compared with PLA ingestion. The ERK pathway (phosphorylation of ERK1/2 [Thr202/Tyr204], RSK [Ser380], and p70S6K [Thr421/Ser424]) was markedly activated immediately after resistance exercise, without any effect of CHO supplementation. The phosphorylation state of AKT (Thr308) was unchanged postexercise in the PLA trial and increased at 3 hr of recovery above resting with ingestion of CHO compared with PLA. Despite stimulating-marked phosphorylation of AKT, CHO ingestion did not enhance resistance exercise–induced phosphorylation of p70S6K (Thr389) and rpS6 (Ser235/236 and Ser240/244). Conclusion: CHO supplementation after resistance exercise and hyperinsulinemia does not influence the ERK pathway nor the mTORC1 target p70S6K and its downstream proteins, despite the increased AKT phosphorylation.

Keywordsclinical trial; insulin; muscle hypertrophy; protein synthesis; recovery; skeletal muscle
Year2019
JournalInternational Journal of Sport Nutrition and Exercise Metabolism
Journal citation29 (6), pp. 664 - 670
PublisherHuman Kinetics, Inc.
ISSN1526-484X
Digital Object Identifier (DOI)https://doi.org/10.1123/ijsnem.2019-0075
Scopus EID2-s2.0-85076429724
Page range664 - 670
Research GroupMary MacKillop Institute for Health Research
Publisher's version
File Access Level
Controlled
Place of publicationUnited States of America
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