Related Experiment Videos
Acute hyperglycemia enhances proteolysis in normal man
P J Flakoll1, J O Hill, N N Abumrad
1Department of Surgery, Vanderbilt University Medical Center, Nashville, Tennessee 37232.
The American Journal of Physiology
|November 1, 1993
Summary
Hyperinsulinemia with hyperglycemia significantly increases protein breakdown (proteolysis) in the body. However, this condition does not affect protein synthesis or energy expenditure from protein and carbohydrates.
Area of Science:
- Metabolic Physiology
- Nutritional Biochemistry
- Endocrinology
Background:
- Hyperinsulinemia and hyperglycemia are common metabolic states.
- Understanding their combined effects on protein and carbohydrate metabolism is crucial.
Purpose of the Study:
- To assess the influence of hyperinsulinemic-hyperglycemia on protein and carbohydrate homeostasis.
- To investigate the impact of elevated glucose levels on proteolysis and protein synthesis during hyperinsulinemia.
Main Methods:
- Utilized stable isotope tracers (L-[1-13C]-leucine and [3-3H]glucose) and indirect calorimetry.
- Administered continuous insulin infusion to healthy volunteers to achieve maximal effects.
- Manipulated plasma glucose levels to basal and twofold basal concentrations.
Main Results:
- Hyperinsulinemia suppressed endogenous leucine appearance by 80% (period I) and 44% (period II).
- Hyperglycemia (twofold basal) significantly stimulated proteolysis threefold.
- Neither protein synthesis nor oxidation rates were altered by the experimental conditions.
- Hepatic glucose production was suppressed, with increased protein and carbohydrate oxidation and decreased lipid oxidation.
Conclusions:
- Acute elevations in plasma glucose during hyperinsulinemia markedly stimulate whole-body proteolysis.
- Protein synthesis and overall energy substrate utilization are significantly impacted by these metabolic conditions.