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Beneficial effects of resistance exercise on glycemic control are not further improved by protein ingestion.

Breen L, Philp A, Shaw CS, Jeukendrup AE, Baar K, Tipton KD - PLoS ONE (2011)

Bottom Line: Plasma insulin response was 13±2 and 21±4% lower for EX and CON, respectively, compared with EX+PRO.Glucose disappearance from the circulation was ∼12% greater in EX and EX+PRO compared with CON.However, co-ingesting protein during a high-glucose load does not augment this response at 24 h post-exercise in healthy, insulin-sensitive individuals.

View Article: PubMed Central - PubMed

Affiliation: School of Sport and Exercise Sciences, University of Birmingham, Birmingham, United Kingdom.

ABSTRACT

Purpose: To investigate the mechanisms underpinning modifications in glucose homeostasis and insulin sensitivity 24 h after a bout of resistance exercise (RE) with or without protein ingestion.

Methods: Twenty-four healthy males were assigned to a control (CON; n = 8), exercise (EX; n = 8) or exercise plus protein condition (EX+PRO; n = 8). Muscle biopsy and blood samples were obtained at rest for all groups and immediately post-RE (75% 1RM, 8×10 repetitions of leg-press and extension exercise) for EX and EX+PRO only. At 24 h post-RE (or post-resting biopsy for CON), a further muscle biopsy was obtained. Participants then consumed an oral glucose load (OGTT) containing 2 g of [U-¹³C] glucose during an infusion of 6, 6-[²H₂] glucose. Blood samples were obtained every 10 min for 2 h to determine glucose kinetics. EX+PRO ingested an additional 25 g of intact whey protein with the OGTT. A final biopsy sample was obtained at the end of the OGTT.

Results: Fasted plasma glucose and insulin were similar for all groups and were not different immediately post- and 24 h post-RE. Following RE, muscle glycogen was 26±8 and 19±6% lower in EX and EX+PRO, respectively. During OGTT, plasma glucose AUC was lower for EX and EX+PRO (75.1±2.7 and 75.3±2.8 mmol·L⁻¹∶120 min, respectively) compared with CON (90.6±4.1 mmol·L⁻¹∶120 min). Plasma insulin response was 13±2 and 21±4% lower for EX and CON, respectively, compared with EX+PRO. Glucose disappearance from the circulation was ∼12% greater in EX and EX+PRO compared with CON. Basal 24 h post-RE and insulin-stimulated PAS-AS160/TBC1D4 phosphorylation was greater for EX and EX+PRO.

Conclusions: Prior RE improves glycemic control and insulin sensitivity through an increase in the rate at which glucose is disposed from the circulation. However, co-ingesting protein during a high-glucose load does not augment this response at 24 h post-exercise in healthy, insulin-sensitive individuals.

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Signalling protein phosphorylation of (A) Aktser473, (B) PAS-AS160/TBC1D4, (C) p70S6KThr389 and (D) PRAS40Thr246 from muscle samples taken at 4 different time points.Groups as per Table 1. Values are means ± SEM; n = 6 per group. Means with different letters are significantly different from each other (P<0.05). *: significantly lower phosphorylation for CON compared with EX and EX+PRO (P<0.05).
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pone-0020613-g006: Signalling protein phosphorylation of (A) Aktser473, (B) PAS-AS160/TBC1D4, (C) p70S6KThr389 and (D) PRAS40Thr246 from muscle samples taken at 4 different time points.Groups as per Table 1. Values are means ± SEM; n = 6 per group. Means with different letters are significantly different from each other (P<0.05). *: significantly lower phosphorylation for CON compared with EX and EX+PRO (P<0.05).

Mentions: Basal PAS-AS160/TBC1D4 phosphorylation (Day 1) was similar for all groups (Figure 6A). Compared with basal, AS160/TBC1D4 phosphorylation did not change immediately post-exercise but was increased at 24 h post-exercise for EX and EX+PRO only (P<0.05) and was greater compared with CON (P<0.01). At 26 h post-exercise, following OGTT, AS160/TBC1D4 phosphorylation increased by 1.4-fold for CON and 1.3-fold for EX and EX+PRO compared with 24 h post-exercise (P<0.05) and was greater compared with CON (P<0.05). Basal Aktser473 phosphorylation (Day 1) was similar for all groups (Figure 6B). Compared with basal, Akt phosphorylation did not change immediately post- and 24 h post-exercise in all groups. At 26 h post-exercise, following OGTT, Akt phosphorylation increased by 2.2-, 2.3 and 1.9-fold for CON, EX and EX+PRO, respectively, compared with 24 h post-exercise (P<0.05). Akt phosphorylation at 26 h post-exercise was greater for EX and EX+PRO compared with CON (P<0.05). Basal p70S6KThr389 and PRAS40Thr246 phosphorylation (Day 1) was similar for all groups (Figure 6C and 6D, respectively). Compared with basal, p70S6K and PRAS40 phosphorylation was not different immediately-, 24 h- or 26 h-post exercise. There was no between-group difference in p70S6K or PRAS40 phosphorylation immediately-, 24 h- or 26 h-post exercise. All representative western blot images are presented in Figure 7.


Beneficial effects of resistance exercise on glycemic control are not further improved by protein ingestion.

Breen L, Philp A, Shaw CS, Jeukendrup AE, Baar K, Tipton KD - PLoS ONE (2011)

Signalling protein phosphorylation of (A) Aktser473, (B) PAS-AS160/TBC1D4, (C) p70S6KThr389 and (D) PRAS40Thr246 from muscle samples taken at 4 different time points.Groups as per Table 1. Values are means ± SEM; n = 6 per group. Means with different letters are significantly different from each other (P<0.05). *: significantly lower phosphorylation for CON compared with EX and EX+PRO (P<0.05).
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Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3119062&req=5

pone-0020613-g006: Signalling protein phosphorylation of (A) Aktser473, (B) PAS-AS160/TBC1D4, (C) p70S6KThr389 and (D) PRAS40Thr246 from muscle samples taken at 4 different time points.Groups as per Table 1. Values are means ± SEM; n = 6 per group. Means with different letters are significantly different from each other (P<0.05). *: significantly lower phosphorylation for CON compared with EX and EX+PRO (P<0.05).
Mentions: Basal PAS-AS160/TBC1D4 phosphorylation (Day 1) was similar for all groups (Figure 6A). Compared with basal, AS160/TBC1D4 phosphorylation did not change immediately post-exercise but was increased at 24 h post-exercise for EX and EX+PRO only (P<0.05) and was greater compared with CON (P<0.01). At 26 h post-exercise, following OGTT, AS160/TBC1D4 phosphorylation increased by 1.4-fold for CON and 1.3-fold for EX and EX+PRO compared with 24 h post-exercise (P<0.05) and was greater compared with CON (P<0.05). Basal Aktser473 phosphorylation (Day 1) was similar for all groups (Figure 6B). Compared with basal, Akt phosphorylation did not change immediately post- and 24 h post-exercise in all groups. At 26 h post-exercise, following OGTT, Akt phosphorylation increased by 2.2-, 2.3 and 1.9-fold for CON, EX and EX+PRO, respectively, compared with 24 h post-exercise (P<0.05). Akt phosphorylation at 26 h post-exercise was greater for EX and EX+PRO compared with CON (P<0.05). Basal p70S6KThr389 and PRAS40Thr246 phosphorylation (Day 1) was similar for all groups (Figure 6C and 6D, respectively). Compared with basal, p70S6K and PRAS40 phosphorylation was not different immediately-, 24 h- or 26 h-post exercise. There was no between-group difference in p70S6K or PRAS40 phosphorylation immediately-, 24 h- or 26 h-post exercise. All representative western blot images are presented in Figure 7.

Bottom Line: Plasma insulin response was 13±2 and 21±4% lower for EX and CON, respectively, compared with EX+PRO.Glucose disappearance from the circulation was ∼12% greater in EX and EX+PRO compared with CON.However, co-ingesting protein during a high-glucose load does not augment this response at 24 h post-exercise in healthy, insulin-sensitive individuals.

View Article: PubMed Central - PubMed

Affiliation: School of Sport and Exercise Sciences, University of Birmingham, Birmingham, United Kingdom.

ABSTRACT

Purpose: To investigate the mechanisms underpinning modifications in glucose homeostasis and insulin sensitivity 24 h after a bout of resistance exercise (RE) with or without protein ingestion.

Methods: Twenty-four healthy males were assigned to a control (CON; n = 8), exercise (EX; n = 8) or exercise plus protein condition (EX+PRO; n = 8). Muscle biopsy and blood samples were obtained at rest for all groups and immediately post-RE (75% 1RM, 8×10 repetitions of leg-press and extension exercise) for EX and EX+PRO only. At 24 h post-RE (or post-resting biopsy for CON), a further muscle biopsy was obtained. Participants then consumed an oral glucose load (OGTT) containing 2 g of [U-¹³C] glucose during an infusion of 6, 6-[²H₂] glucose. Blood samples were obtained every 10 min for 2 h to determine glucose kinetics. EX+PRO ingested an additional 25 g of intact whey protein with the OGTT. A final biopsy sample was obtained at the end of the OGTT.

Results: Fasted plasma glucose and insulin were similar for all groups and were not different immediately post- and 24 h post-RE. Following RE, muscle glycogen was 26±8 and 19±6% lower in EX and EX+PRO, respectively. During OGTT, plasma glucose AUC was lower for EX and EX+PRO (75.1±2.7 and 75.3±2.8 mmol·L⁻¹∶120 min, respectively) compared with CON (90.6±4.1 mmol·L⁻¹∶120 min). Plasma insulin response was 13±2 and 21±4% lower for EX and CON, respectively, compared with EX+PRO. Glucose disappearance from the circulation was ∼12% greater in EX and EX+PRO compared with CON. Basal 24 h post-RE and insulin-stimulated PAS-AS160/TBC1D4 phosphorylation was greater for EX and EX+PRO.

Conclusions: Prior RE improves glycemic control and insulin sensitivity through an increase in the rate at which glucose is disposed from the circulation. However, co-ingesting protein during a high-glucose load does not augment this response at 24 h post-exercise in healthy, insulin-sensitive individuals.

Show MeSH
Related in: MedlinePlus