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

2019 ◽  
Vol 29 (6) ◽  
pp. 664-670 ◽  
Author(s):  
Vandre C. Figueiredo ◽  
Michelle M. Farnfield ◽  
Megan L.R. Ross ◽  
Petra Gran ◽  
Shona L. Halson ◽  
...  
Keyword(s):  
Resistance Exercise ◽  
Mammalian Target Of Rapamycin ◽  
Erk Pathway ◽  
Double Blind ◽  
Carbohydrate Ingestion ◽  
Akt Phosphorylation ◽  
Extracellular Signal ◽  
Exercise Muscle ◽  
Exercise Induced ◽  
Double Blinded

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.

scholarly journals Leucine-enriched essential amino acid and carbohydrate ingestion following resistance exercise enhances mTOR signaling and protein synthesis in human muscle

2008 ◽  
Vol 294 (2) ◽  
pp. E392-E400 ◽  
Author(s):  
Hans C. Dreyer ◽  
Micah J. Drummond ◽  
Bart Pennings ◽  
Satoshi Fujita ◽  
Erin L. Glynn ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Resistance Exercise ◽  
Muscle Protein ◽  
Muscle Protein Synthesis ◽  
Mammalian Target Of Rapamycin ◽  
Essential Amino Acids ◽  
Mtor Signaling ◽  
Control Group ◽  
Carbohydrate Ingestion ◽  
Akt Phosphorylation

We recently showed that resistance exercise and ingestion of essential amino acids with carbohydrate (EAA+CHO) can independently stimulate mammalian target of rapamycin (mTOR) signaling and muscle protein synthesis in humans. Providing an EAA+CHO solution postexercise can further increase muscle protein synthesis. Therefore, we hypothesized that enhanced mTOR signaling might be responsible for the greater muscle protein synthesis when leucine-enriched EAA+CHOs are ingested during postexercise recovery. Sixteen male subjects were randomized to one of two groups (control or EAA+CHO). The EAA+CHO group ingested the nutrient solution 1 h after resistance exercise. mTOR signaling was assessed by immunoblotting from repeated muscle biopsy samples. Mixed muscle fractional synthetic rate (FSR) was measured using stable isotope techniques. Muscle protein synthesis and 4E-BP1 phosphorylation during exercise were significantly reduced ( P < 0.05). Postexercise FSR was elevated above baseline in both groups at 1 h but was even further elevated in the EAA+CHO group at 2 h postexercise ( P < 0.05). Increased FSR was associated with enhanced phosphorylation of mTOR and S6K1 ( P < 0.05). Akt phosphorylation was elevated at 1 h and returned to baseline by 2 h in the control group, but it remained elevated in the EAA+CHO group ( P < 0.05). 4E-BP1 phosphorylation returned to baseline during recovery in control but became elevated when EAA+CHO was ingested ( P < 0.05). eEF2 phosphorylation decreased at 1 and 2 h postexercise to a similar extent in both groups ( P < 0.05). Our data suggest that enhanced activation of the mTOR signaling pathway is playing a role in the greater synthesis of muscle proteins when resistance exercise is followed by EAA+CHO ingestion.

Influence of Carbohydrate Ingestion on Cytokine Responses Following Acute Resistance Exercise

2003 ◽  
Vol 13 (4) ◽  
pp. 454-465 ◽  
Author(s):  
Marcia A. Chan ◽  
Alexander J. Koch ◽  
Stephen H. Benedict ◽  
Jeffrey A. Potteiger
Keyword(s):  
Resistance Exercise ◽  
High Intensity ◽  
Mononuclear Cells ◽  
Interleukin 2 ◽  
Double Blind ◽  
Peripheral Blood Mononuclear ◽  
Carbohydrate Ingestion ◽  
Post Exercise ◽  
Carbohydrate Supplementation ◽  
Interleukin 5

The effect of carbohydrate supplementation (CHO) on interleukin 2 (IL-2) and interleukin 5 (IL-5) secretion following acute resistance exercise was examined in 9 resistance-trained males. Subjects completed a randomized, double-blind protocol with exercise separated by 14 days. The exercise consisted of a high intensity, short rest interval squat workout. Subjects consumed 1.0 g · kg body mass-1 CHO or an equal volume of placebo (PLC) 10 min prior to and 10 min following exercise. Blood was collected at rest (REST), immediately post exercise (POST), and at 1.5 h of recovery (1.5 h POST). Isolated peripheral blood mononuclear cells were stimulated with PHA and assayed for IL-2 and IL-5 secretion. IL-2 secretion was significantly decreased at POST for both the PLC and CHO groups. However, the degree of decrease was less in the CHO group (16%) than in the PLC group (48%), and this difference was statistically significant. These responses were transient, and the values returned to normal by 1.5 h POST. A mild and transient but significant decrease in IL-5 secretion by the PLC group was observed at POST (26%) compared to REST. No significant decrease was observed in IL-5 secretion for CHO from REST to POST (12%). These data support a possible effect of carbohydrate supplementation on IL-2 and IL-5 secretion following high-intensity resistance exercise.

Essential Amino Acid-Carbohydrate Ingestion Prior to Resistance Exercise, Muscle AMPK Activity and Protein Synthesis

2006 ◽  
Vol 38 (Supplement) ◽  
pp. S112
Author(s):  
Satoshi Fujita ◽  
Hans C. Dreyer ◽  
Jerson G. Cadenas ◽  
Jessica Lee ◽  
Erin L. Glynn ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Amino Acid ◽  
Resistance Exercise ◽  
Essential Amino Acid ◽  
Carbohydrate Ingestion ◽  
Ampk Activity ◽  
Exercise Muscle

Minimal Influence of Carbohydrate Ingestion on the Immune Response Following Acute Resistance Exercise

2001 ◽  
Vol 11 (2) ◽  
pp. 149-161 ◽  
Author(s):  
Alexander J. Koch ◽  
Jeffrey A. Potteiger ◽  
Marcia A. Chan ◽  
Stephen H. Benedict ◽  
Bruce B. Frey
Keyword(s):  
Resistance Exercise ◽  
Plasma Glucose ◽  
High Intensity ◽  
Lymphocyte Proliferation ◽  
Treatment Time ◽  
Exercise Session ◽  
Lymphocyte Response ◽  
Double Blind ◽  
Carbohydrate Ingestion ◽  
Post Exercise

The effect of carbohydrate supplementation (CHO) on the lymphocyte response to acute resistance exercise was examined in 10 resistance-trained males. Subjects completed a randomized double-blind protocol with sessions separated by 14 days. The exercise session consisted of a high intensity, short rest interval squat workout. Subjects consumed 1.0 g · kg body mass−1 CHO or an equal volume of placebo (PLC) 10 min prior to and 10 min following exercise. Blood was collected at rest (REST), immediately post exercise (POST), and at 1.5 hours and 4.0 hours of recovery, and analyzed for plasma glucose, serum cortisol, leukocyte subsets, and phytohemagglutinin (PHA)-stimulated lymphocyte proliferation. A significant Treatment × Time effect was observed for lymphocyte proliferation between CHO and PLC, but post hoc analyses revealed no between-treatment differences at any post-exercise time point. Lymphocyte proliferation was significantly depressed below REST at POST (−39.2% for PLC, −25.7% for CHO). Significant fluctuations in leukocyte subset trafficking were observed for both treatments at POST, 1.5 hours, and 4.0 hours. Plasma glucose was significantly increased POST in CHO compared to PLC. Cortisol was significantly increased from REST to POST in both treatments. These data support a minimal effect of carbohydrate ingestion on the lymphocyte response to high-intensity resistance exercise.

Resistance exercise, muscle loading/unloading and the control of muscle mass

2006 ◽  
Vol 42 ◽  
pp. 61-74 ◽  
Author(s):  
Keith Baar ◽  
Gustavo Nader ◽  
Sue Bodine
Keyword(s):  
Protein Synthesis ◽  
Resistance Exercise ◽  
Muscle Mass ◽  
Translation Initiation ◽  
Muscle Protein ◽  
Mammalian Target Of Rapamycin ◽  
Complete Breakdown ◽  
Muscle Loading ◽  
The Difference ◽  
Exercise Muscle

Muscle mass is determined by the difference between the rate of protein synthesis and degradation. If synthesis is greater than degradation, muscle mass will increase (hypertrophy) and when the reverse is true muscle mass will decrease (atrophy). Following resistance exercise/increased loading there is a transient increase in protein synthesis within muscle. This change in protein synthesis correlates with an increase in the activity of protein kinase B/Akt and mTOR (mammalian target of rapamycin). mTOR increases protein synthesis by increasing translation initiation and by inducing ribosomal biogenesis. By contrast, unloading or inactivity results in a decrease in protein synthesis and a significant increase in muscle protein breakdown. The decrease in synthesis is due in part to the inactivation of mTOR and therefore a decrease in translation initiation, but also to a decrease in the rate of translation elongation. The increase in degradation is the result of a co-ordinated response of the calpains, lysosomal proteases and the ATP-dependent ubiquitin-proteosome. Caspase 3 and the calpains act upstream of the ubiquitin–proteosome system to assist in the complete breakdown of the myofibrillar proteins. Two muscle specific E3 ubiquitin ligases, MuRF1 and MAFbx/atrogen-1, have been identified as key regulators of muscle atrophy. In this chapter, these pathways and how the balance between anabolism and catabolism is affected by loading and unloading will be discussed.

scholarly journals Follicle-Stimulating Hormone Increases Tuberin Phosphorylation and Mammalian Target of Rapamycin Signaling through an Extracellular Signal-Regulated Kinase-Dependent Pathway in Rat Granulosa Cells

Endocrinology ◽  
2007 ◽  
Vol 148 (8) ◽  
pp. 3950-3957 ◽  
Author(s):  
Pradeep P. Kayampilly ◽  
K. M. J. Menon
Keyword(s):  
Granulosa Cells ◽  
Mammalian Target Of Rapamycin ◽  
Fold Increase ◽  
Mtor Signaling ◽  
Target Of Rapamycin ◽  
Akt Phosphorylation ◽  
Downstream Target ◽  
Upstream Regulator ◽  
Extracellular Signal ◽  
Dependent Pathway

FSH-mediated regulation of mammalian target of rapamycin (mTOR) signaling in proliferating granulosa cells and the effect of dihydrotestosterone (DHT) on this pathway were examined. Inhibiting mTOR activation using rapamycin significantly reduced the FSH-mediated increase in cyclin D2 mRNA expression, suggesting that mTOR plays a role in the FSH-mediated increase in granulosa cell proliferation. FSH treatment of granulosa cells showed a 2-fold increase in phosphorylation of p70S6 kinase (p70S6K), the downstream target of mTOR. The increase in p70S6K phosphorylation by FSH treatment was abolished by prior exposure to DHT, suggesting that DHT inhibits FSH-mediated activation of mTOR signaling in cultured granulosa cells. The effect of FSH and DHT treatment on tuberin (TSC2), the upstream regulator of mTOR, was then examined. FSH treatment increased TSC2 phosphorylation, and pretreatment with DHT for 24 h reduced this stimulation. These results indicate that reduced p70S6K phosphorylation observed in DHT-treated cells might be the result of reduced TSC2 phosphorylation. Because Akt is the upstream activator of TSC2 phosphorylation, the effect of Akt inhibition was examined to test whether FSH-mediated TSC2 phosphorylation proceeds through an Akt-dependent pathway. Our results show that inhibiting Akt phosphorylation did not block FSH-stimulated TSC2 phosphorylation, whereas ERK inhibition reduced FSH-mediated stimulation. These results demonstrate the involvement of ERK rather than Akt in FSH-mediated TSC2 phosphorylation in granulosa cells. Based on these observations, we conclude that in granulosa cells, FSH uses a protein kinase A-/ERK-dependent pathway to stimulate TSC2 phosphorylation and mTOR signaling, and DHT treatment significantly reduces this response.

scholarly journals Administration of Apple Polyphenol Supplements for Skin Conditions in Healthy Women: A Randomized, Double-Blind, Placebo-Controlled Clinical Trial

Nutrients ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 1071
Author(s):  
Toshihiko Shoji ◽  
Saeko Masumoto ◽  
Nina Moriichi ◽  
Yasuyuki Ohtake ◽  
Tomomasa Kanda
Keyword(s):  
Clinical Trial ◽  
Uv Irradiation ◽  
Skin Pigmentation ◽  
Controlled Clinical Trial ◽  
Continuous Administration ◽  
Double Blind ◽  
Healthy Women ◽  
Dependent Relationship ◽  
Skin Conditions ◽  
Double Blinded

This clinical study was performed to evaluate the effects of continuous apple polyphenol (AP) administration on facial skin conditions and pigmentation induced by ultraviolet (UV) irradiation in healthy women participants. Participants (n = 65, age 20–39 years) were randomized to receive tablets containing AP (300 or 600 mg/day) or placebo in a double-blinded, placebo-controlled clinical trial. Continuous administration of AP for 12 weeks significantly prevented UV irradiation induced skin pigmentation (erythema value, melanin value, L value), although a dose-dependent relationship was not clearly observed. In contrast, no significant differences were detected between the groups with regard to water content and trans-epidermal water loss. Our study demonstrated that APs and their major active compounds, procyanidins, have several health benefits. Here, we report that continuous administration of AP for 12 weeks alleviated UV irradiation induced skin pigmentation, when compared with placebo, in healthy women.

The Acute Effects of Androstenedione Supplementation in Healthy Young Males

2000 ◽  
Vol 25 (1) ◽  
pp. 68-78 ◽  
Author(s):  
Craig S. Ballantyne ◽  
Stuart M. Phillips ◽  
Jay R. Macdonald ◽  
Mark A. Tarnopolsky ◽  
J. Duncan Macdougall
Keyword(s):  
Luteinizing Hormone ◽  
Resistance Exercise ◽  
Elevated Plasma ◽  
Acute Effects ◽  
Double Blind ◽  
Male Athletes ◽  
Young Males ◽  
Plasma Estradiol ◽  
Key Words Testosterone ◽  
Heavy Resistance Exercise

We examined the effects of androstenedione supplementation on the hormonal profile of 10 males and its interaction with resistance exercise. Baseline testosterone, luteinizing hormone, estradiol, and androstenedione concentrations were established by venous sampling at 3 hr intervals over 24 hr. Subjects ingested 200 mg of androstenedione daily for 2 days, with second and third day blood samples. Two weeks later, they ingested androstenedione or a placebo for 2 days, in a double-blind, cross-over design. On day 2, they performed heavy resistance exercise with blood sampled before, after, and 90 min post. The supplement elevated plasma androstenedione 2-3-fold and luteinizing hormone ∼70% but did not alter testosterone concentration. Exercise elevated testosterone, with no difference between conditions. Exercise in the supplemented condition significantly elevated plasma estradiol by ∼83% for 90 min. Androstenedione supplementation, thus, is unlikely to provide male athletes with any anabolic benefit and, with heavy resistance exercise, elevates estrogen. Key Words: testosterone, luteinizing hormone, estradiol, fluid shifts, resistance exercise

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