Related Experiment Videos
Insulin and glucagon immunoreactivity during high-intensity exercise under opiate blockade
T J Angelopoulos1, R J Robertson, F L Goss
1Laboratory of Applied Physiology, The University of Southern Mississippi, Hattiesburg 39406, USA.
Summary
Endogenous opioids may increase glucagon levels during intense exercise. This study found higher glucagon during exercise with a placebo compared to naloxone, suggesting opioid involvement in exercise-induced hormonal changes.
Area of Science:
- Exercise Physiology
- Endocrinology
- Neuroscience
Background:
- Endogenous opioids play a role in modulating physiological responses during exercise.
- Understanding hormonal regulation, specifically insulin and glucagon, during intense physical activity is crucial.
Purpose of the Study:
- To investigate the effect of endogenous opioids on insulin and glucagon immunoreactivity during high-intensity exercise.
- To determine if naloxone administration alters hormonal responses compared to a placebo during treadmill exercise.
Main Methods:
- A double-blind, placebo-controlled study involving eight fit men performing two 20-minute treadmill exercise trials at 80% VO2max.
- Subjects received either naloxone or a placebo intravenously before exercise, with blood samples collected pre-exercise and post-exercise.
- Measurements included insulin and glucagon levels, alongside maximum oxygen consumption (VO2max) and age.
Main Results:
- Both trials showed increased glucagon and decreased insulin during exercise compared to pre-exercise levels.
- Glucagon levels were significantly higher in the placebo trial compared to the naloxone trial.
- No significant difference in insulin levels was observed between the placebo and naloxone trials during exercise.
Conclusions:
- Endogenous opioids appear to augment the exercise-induced glucagon response during intense physical exertion.
- The findings suggest a modulatory role for endogenous opioids in the regulation of glucagon secretion during strenuous exercise.