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Human splanchnic amino-acid metabolism
Evelien P J G Neis1,2, S Sabrkhany3,4, I Hundscheid2
1Top Institute Food and Nutrition, P.O. Box 557, 6700 AN, Wageningen, The Netherlands.
Amino Acids
|October 8, 2016
Summary
Human amino acid metabolism was studied by measuring splanchnic interorgan handling. The small intestine takes up glutamine, while the kidneys release serine and alanine, revealing organ-specific amino acid processing.
Area of Science:
- Metabolic physiology
- Human biochemistry
- Interorgan metabolism
Background:
- Plasma amino acid levels are linked to metabolic disorders like obesity and type 2 diabetes.
- Understanding human amino acid metabolism is crucial for metabolic health.
- Splanchnic interorgan amino acid handling requires further investigation.
Purpose of the Study:
- To elucidate splanchnic interorgan amino acid handling in humans.
- To quantify amino acid exchange across major abdominal organs.
- To investigate the functional integrity of the glutamine-citrulline pathway in the human gut.
Main Methods:
- Blood samples were collected from multiple veins (portal, hepatic, mesenteric, splenic, renal) and the radial artery during surgery.
- Liquid chromatography was used to measure concentrations of 21 amino acids.
- Organ-specific amino acid metabolism was assessed by calculating the arteriovenous concentration difference.
Main Results:
- The small intestine demonstrated significant uptake of glutamine (121.0 ± 23.8 µmol/L) and release of citrulline (-36.1 ± 4.6 µmol/L).
- The kidneys released substantial amounts of serine (-58.0 ± 4.4 µmol/L) and alanine (-61.8 ± 5.2 µmol/L), along with tyrosine.
- The liver exhibited a minor uptake of citrulline (4.8 ± 1.6 µmol/L), and the spleen released taurine.
Conclusions:
- The glutamine-citrulline pathway is functional in the human small intestine but not in the colon.
- Organ-specific amino acid metabolism varies significantly, with distinct roles for the small intestine, liver, kidneys, and spleen.
- This study provides novel insights into integrative amino acid physiology in humans.
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