Forskning
Udskriv Udskriv
Switch language
Rigshospitalet - en del af Københavns Universitetshospital
Udgivet

Heterogeneity in subcellular muscle glycogen utilisation during exercise impacts endurance capacity in men

Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

DOI

  1. Regulation of plasma volume in male lowlanders during 4 days of exposure to hypobaric hypoxia equivalent to 3500 m altitude

    Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

  2. KATP channels modulate cerebral blood flow and oxygen delivery during isocapnic hypoxia in humans

    Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

  3. Blood-brain barrier permeability measured using dynamic contrast-enhanced magnetic resonance imaging: a validation study

    Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

  4. Human brain blood flow and metabolism during isocapnic hyperoxia: the role of reactive oxygen species

    Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

  5. Lower body negative pressure to safely reduce intracranial pressure

    Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

  1. Effect of insulin on natriuretic peptide gene expression in porcine heart

    Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

  2. S100B and brain derived neurotrophic factor in monozygotic twins with, at risk of and without affective disorders

    Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

  3. Sacubitril/valsartan increases postprandial gastrin and cholecystokinin in plasma

    Publikation: Bidrag til tidsskriftTidsskriftartikelForskningpeer review

  • Rasmus Jensen
  • Niels Ørtenblad
  • Marie-Louise Holleufer Stausholm
  • Mette Carina Skjaerbaek
  • Daniel Nykvist Larsen
  • Mette Hansen
  • Hans-Christer Holmberg
  • Peter Plomgaard
  • Joachim Nielsen
Vis graf over relationer

KEY POINTS: When muscle biopsies first began to be used routinely in research on exercise physiology five decades ago, it soon become clear that the muscle content of glycogen is an important determinant of exercise performance. Glycogen particles are stored in distinct pools within the muscles, but the role of each pool during exercise and how this is affected by diet is unknown. Here, the effects of diet and exercise on these pools, as well as their relation to endurance during prolonged cycling were examined. We demonstrate here that an improved endurance capacity with high carbohydrate loading is associated with a temporal shift in the utilisation of the distinct stores of glycogen pools and is closely linked to the content of the glycogen pool closest to actin and myosin (intramyofibrillar glycogen). These findings highlight the functional importance of distinguishing between different subcellular microcompartments of glycogen in individual muscle fibres.

ABSTRACT: In muscle cells, glycogen is stored in three distinct subcellular pools: between or within myofibrils (inter- and intramyofibrillar glycogen, respectively) or beneath the sarcolemma (subsarcolemmal glycogen) and these pools may well have different functions. Here, we investigated the effect of diet and exercise on the content of these distinct pools and their relation to endurance capacity in type 1 and 2 muscle fibres. Following consumption of three different diets (normal, mixed diet = MIX, high in carbohydrate = HIGH, or low in carbohydrate = LOW) for 72 h, 11 men cycled at 75% of V ̇ O 2 max until exhaustion. The volumetric content of the glycogen pools in muscle biopsies obtained before, during, and after exercise were quantified by transmission electron micrographs. The mean (SD) time to exhaustion was 150 (30), 112 (22), and 69 (18) minutes in the HIGH, MIX and LOW trials, respectively (P < 0.001). As shown by multiple regression analyses, the intramyofibrillar glycogen content in type 1 fibres, particularly after 60 min of exercise, correlated most strongly with time to exhaustion. In the HIGH trial, intramyofibrillar glycogen was spared during the initial 60 min of exercise, which was associated with levels and utilisation of subsarcolemmal glycogen above normal. In all trials, utilisation of subsarcolemmal and intramyofibrillar glycogen was more pronounced than that of intermyofibrillar glycogen in relative terms. In conclusion, the muscle pool of intramyofibrillar glycogen appears to be the most important for endurance capacity in humans. In addition, a local abundance of subsarcolemmal glycogen reduces the utilisation of intramyofibrillar glycogen during exercise.

OriginalsprogEngelsk
TidsskriftThe Journal of physiology
Vol/bind598
Udgave nummer19
Sider (fra-til)4271-4292
Antal sider22
ISSN0022-3751
DOI
StatusUdgivet - okt. 2020

Bibliografisk note

© 2020 The Authors. The Journal of Physiology © 2020 The Physiological Society.

ID: 61421259