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Threonine-deficient diets induced changes in hepatic bioenergetics
Catherine M Ross-Inta1, Yi-Fan Zhang, Andrew Almendares
1Department of Molecular Biosciences, School of Veterinary Medicine, University of California Davis, Davis, California 95616, USA.
American Journal of Physiology. Gastrointestinal and Liver Physiology
|February 21, 2009
Summary
Threonine-deficient diets specifically uncouple liver mitochondria, enhancing ATP production from fat metabolism. This biochemical adaptation supports protein synthesis when essential amino acids are scarce.
Area of Science:
- Biochemistry
- Nutritional Science
- Mitochondrial Biology
Background:
- Amino acid-deficient diets are known to reduce food intake.
- Limited research exists on mitochondrial biochemical changes induced by such diets.
Purpose of the Study:
- To investigate mitochondrial function in rats fed varying levels of threonine (Thr).
- To determine the impact of threonine deficiency on liver and heart mitochondria.
Main Methods:
- Rats were fed diets with threonine levels at 0, 30, 60, and 140% of the requirement.
- Mitochondrial function was assessed, particularly focusing on uncoupling with NADH-linked substrates.
Main Results:
- Threonine-deficient diets induced specific mitochondrial uncoupling in the liver, especially with NADH-linked substrates.
- This effect was not observed in heart mitochondria, except in the threonine-devoid diet.
- Mitochondrial uncoupling favors nutrient utilization with higher FADH-to-NADH ratios, like fat.
Conclusions:
- Threonine deficiency triggers liver mitochondrial uncoupling to optimize energy utilization.
- This mechanism enhances the use of the limiting amino acid (threonine) for protein synthesis when dietary protein quality is low.
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