Availability of amino acids supplied intravenously in healthy man as synthetic dipeptides: kinetic evaluation of L-alanyl-L-glutamine and glycyl-L-tyrosine.
1. For the first time utilization of intravenously administered L-alanyl-L-glutamine and glycyl-L-tyrosine was investigated by means of their kinetic behaviour after bolus injection in 10 and 11 apparently healthy male subjects (age 26.6 +/- 5.7 years), respectively. 2. The injection of the synthetic dipeptides was not accompanied by any side effects or complaints. 3. The synthetic dipeptides L-alanyl-L-glutamine and glycyl-L-tyrosine were rapidly cleared from plasma. By applying a monoexponential model the elimination half-lives were found to have very similar values (3.8 +/- 0.5 and 3.4 +/- 0.3 min) whether alanine or glycine was occupying the N-terminal position. The estimated volume of distribution was approximately that of the extracellular space. 4. Peptide disappearance was accompanied by a prompt equimolar increase in the concentrations of the constituent amino acids alanine and glutamine as well as glycine and tyrosine. 5. The study provides firm evidence that L-alanyl-L-glutamine and glycyl-L-tyrosine are rapidly (quantitatively) hydrolysed. The results of this study may indicate a safe and efficient parenteral use of the investigated peptides as sources of free glutamine and free tyrosine.
Albers
S
S
Institute for Biological Chemistry and Nutrition, University of Hohenheim, Stuttgart, F.R.G.
Wernerman
J
J
Stehle
P
P
Vinnars
E
E
Fürst
P
P
D000328:Adult; D000409:Alanine / Q000378:metabolism; D004151:Dipeptides / Q000008:administration & dosage / Q000493:pharmacokinetics*; D005973:Glutamine / Q000378:metabolism; D005998:Glycine / Q000378:metabolism; D006801:Humans; D007262:Infusions, Intravenous; D008297:Male; D013997:Time Factors; D014443:Tyrosine / Q000378:metabolism
D004151:Dipeptides; D005973:Glutamine; D014443:Tyrosine; C022013:glycyltyrosine; D000409:Alanine; D005998:Glycine; C054122:alanylglutamine