Related Experiment Videos
Training effects on muscle glucose transport during exercise
E A Richter1, S Kristiansen, J Wojtaszewski
1Copenhagen Muscle Research Centre, August Krogh Institute, University of Copenhagen, Denmark.
Advances in Experimental Medicine and Biology
|October 22, 1998
Summary
Exercise increases muscle glucose uptake, but endurance training reduces it during submaximal exercise. This occurs because training blunts the exercise-induced increase in glucose transporter type 4 (GLUT4) in muscle cell membranes.
Area of Science:
- Exercise Physiology
- Metabolic Regulation
- Skeletal Muscle Biology
Background:
- Muscle glucose uptake significantly increases during exercise compared to rest.
- This uptake is influenced by exercise intensity and duration, with muscle perfusion playing a key role.
- Glucose transporter type 4 (GLUT4) in the muscle cell membrane is crucial for glucose transport.
Purpose of the Study:
- To investigate the impact of endurance training on muscle glucose uptake during exercise.
- To determine the underlying mechanisms, specifically changes in GLUT4 transporter activity and localization.
Main Methods:
- Comparison of muscle glucose uptake and GLUT4 protein content at rest versus during exercise.
- Assessment of exercise-induced changes in sarcolemmal GLUT4 transporter number.
- Evaluation of muscle perfusion and arterio-venous glucose concentration differences.
Main Results:
- Endurance training decreases muscle glucose uptake at a given submaximal workload.
- This decrease is associated with a blunted increase in sarcolemmal GLUT4 transporter number during exercise.
- Muscle perfusion increases significantly during exercise, contributing to glucose uptake.
Conclusions:
- Endurance training reduces the fraction of muscle GLUT4 translocated to the sarcolemma during submaximal exercise.
- This adaptation may contribute to altered glucose metabolism during exercise in trained individuals.
- Further research is needed to understand these effects at higher exercise intensities.