Transcerebral exchange kinetics of large neutral amino acids during acute inspiratory hypoxia in humans

Rasmus H. Dahl, Ronan M.G. Berg*, Sarah Taudorf, Damian M. Bailey, Carsten Lundby, Mette Christensen, Fin S. Larsen, Kirsten Møller

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

14 Downloads (Pure)


Hypoxaemia is present in many critically ill patients, and may contribute to encephalopathy. Changes in the passage of large neutral amino acids (LNAAs) across the blood-brain barrier (BBB) with an increased cerebral influx of aromatic amino acids into the brain may concurrently be present and also contribute to encephalopathy, but it has not been established whether hypoxaemia per se may trigger such changes. We measured cerebral blood flow (CBF) in 11 healthy men using the Kety-Schmidt technique and obtained paired arterial and jugular-venous blood samples for the determination of LNAAs by high performance liquid chromatography at baseline and after 9 hours of poikilocapnic normobaric hypoxia (12% O2). Transcerebral net exchange was determined by the Fick principle, and transport of LNAAs across the BBB was determined mathematically. Hypoxia increased both the systemic and corresponding cerebral delivery of the aromatic amino acid phenylalanine, and the branched-chain amino acids leucine and isoleucine. Despite this, the transcerebral net exchange values and mathematically derived brain extracellular concentrations for all LNAAs were unaffected. In conclusion, the observed changes in circulating LNAAs triggered by hypoxaemia do not affect the transcerebral exchange kinetics of LNAAs to such an extent that their brain extracellular concentrations are affected.

Original languageEnglish
Pages (from-to)595-600
Number of pages6
JournalScandinavian Journal of Clinical and Laboratory Investigation
Issue number8
Publication statusPublished - 26 Oct 2019


  • (MeSH ID): Aromatic amino acids (D024322)
  • blood-brain barrier (D001812)
  • branched-chain amino acids (D000597)
  • hypoxia (D000860)
  • metabolism (D008660)


Dive into the research topics of 'Transcerebral exchange kinetics of large neutral amino acids during acute inspiratory hypoxia in humans'. Together they form a unique fingerprint.

Cite this