Utilization of N-acetyl-L-tyrosine and glycyl-L-tyrosine during long-term parenteral nutrition in the growing rat

• Published in: The American journal of clinical nutrition Vol. 42; no. 4; pp. 585 - 596
• Main Authors: Neuhäuser, M, Wandira, JA, Göttmann, U, Bässler, KH, Langer, K
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Elsevier Inc 01.10.1985; American Society for Clinical Nutrition
• Subjects: Amino Acids - blood; Anesthesia. Intensive care medicine. Transfusions. Cell therapy and gene therapy; Animals; Applied sciences; Biological and medical sciences; Body Weight; Dipeptides - administration & dosage; Dipeptides - metabolism; Dipeptides - urine; Emergency and intensive care: metabolism and nutrition disorders. Enteral and parenteral nutrition; Exact sciences and technology; Intensive care medicine; Male; Medical sciences; Nitrogen - metabolism; Other techniques and industries; Parenteral Nutrition, Total; Rats; Rats, Inbred Strains; Time Factors; Tyrosine - administration & dosage; Tyrosine - analogs & derivatives; Tyrosine - metabolism; Tyrosine - urine; Tyrosine; Vertebrata; Mammalia; Rat; Aminoacid; Rodentia; Experimental study; Resuscitation; Parenteral administration; Feeding
• ISSN: 0002-9165; 1938-3207
• DOI: 10.1093/ajcn/42.4.585

Utilization of N-acetyl-L-tyrosine and glycyl-L-tyrosine as a source of tyrosine in infusion solutions was tested in rats receiving total parenteral nutrition for 4 wk. The four solutions tested were isonitrogenous and isocaloric. One of the solutions contained an adequate amount of L-phenylalanine; in the other three, two-thirds of the phenylalanine was replaced by a corresponding amount of either glycine, glycyl-L-tyrosine or N-acetyl-L-tyrosine. No differences in weight gain or N-balance could be detected as a result of administering either the solution with glycyl-L-tyrosine or with N-acetyl-L-tyrosine in place of the solution containing an adequate phenylalanine content. The solution in which two-thirds of the L-phenylalanine was replaced by glycine yielded only half of the weight gain and correspondingly reduced values for N-balance. Daily urinary excretion rates for N-acetyl-L-tyrosine and glycyl-L-tyrosine were 11% and 0.5%, respectively, of the infused amount. Plasma amino acid pattern was affected differently by the four solutions. The results indicate that both N-acetyl-L-tyrosine and glycyl-L-tyrosine are efficiently utilized by the rat during total parenteral nutrition.