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Physiological hypercortisolemia increases proteolysis, glutamine, and alanine production
D Darmaun1, D E Matthews, D M Bier
1Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110.
The American Journal of Physiology
|September 1, 1988
Summary
Physiological elevations in cortisol, mimicking stress, increase whole-body protein breakdown and alter amino acid metabolism. This study shows cortisol
Area of Science:
- Biochemistry
- Physiology
- Endocrinology
Background:
- Cortisol is a key stress hormone influencing metabolic processes.
- Understanding cortisol's impact on amino acid kinetics is crucial for managing catabolic states.
Purpose of the Study:
- To investigate the effects of sustained physiological hypercortisolemia on amino acid kinetics in humans.
- To quantify changes in protein breakdown and amino acid synthesis under elevated cortisol levels.
Main Methods:
- Infusion of hydrocortisone to achieve physiological cortisol levels in healthy subjects.
- Measurement of amino acid kinetics using stable isotope tracers (L-leucine, L-phenylalanine, L-glutamine, L-alanine).
- Kinetic measurements performed before, during (12h), and after (60h) cortisol infusion.
Main Results:
- Cortisol infusion significantly increased plasma cortisol, leucine, and phenylalanine flux, indicating increased protein breakdown.
- Glutamine flux rose due to a substantial increase in de novo synthesis.
- Alanine flux increased, primarily driven by enhanced de novo synthesis, particularly at later time points.
Conclusions:
- Sustained physiological hypercortisolemia promotes whole-body protein catabolism.
- Cortisol stimulates de novo synthesis of non-essential amino acids like glutamine and alanine.
- These findings elucidate the complex metabolic adaptations to stress and elevated cortisol.