In vivo utilization of intravenously supplied L-alanyl-L-glutamine in various tissues of the rat.
Isotope studies were performed to investigate the metabolism of the highly soluble and stable synthetic dipeptide L-alanyl-L-glutamine in rats. After intravenous injection of L-alanyl-L-[U-14C]glutamine, the extent of radioactive labeling of nonprotein and protein fractions of plasma, liver, muscle, and kidney as well as of expired CO2 was determined using liquid scintillation counting. Within 40min, the production of 14CO2 reached maximum values. In all tissues investigated, the rapid decline of label in the nonprotein fractions was accompanied by an increase of radioactivity in the protein fractions. Only traces of radioactivity (less than 1%) were detectable in urine. The amount of label recovered (in percent of injected dose) 3h after peptide bolus administration was 56% in CO2, 13% in muscle, 3.1% in liver, 1.9% in plasma, and 0.6% in kidney. Intravenously supplied L-alanyl-L-glutamine is rapidly and efficiently hydrolyzed with subsequent utilization of the liberated glutamine for energy production and the synthesis of proteins. This dipeptide may be useful as a source of the critical but unstable glutamine in parenteral nutrition solutions.
Stehle
P
P
Institute for Biological Chemistry and Nutrition, University of Hohenheim, Stuttgart, FRG.
Ratz
I
I
Fürst
P
P
D000818:Animals; D004151:Dipeptides / Q000008:administration & dosage / Q000378:metabolism*; D004355:Drug Stability; D005260:Female; D005973:Glutamine / Q000008:administration & dosage; D007275:Injections, Intravenous; D010288:Parenteral Nutrition / Q000379:methods; D011506:Proteins / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D014018:Tissue Distribution
D004151:Dipeptides; D011506:Proteins; D005973:Glutamine; C054122:alanylglutamine