Sugar-Amino Acid Complexes in Parenteral Alimentation

Stegink, Lewis D.; Shepherd, James A.; Fry, Larry K.; Filer, L. J.

doi:10.1203/00006450-197404000-00276

Cited by 10 publications

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“…Although these studies with I.-alanyl-I,-tyrosine are restricted to adult animals, the authors believe that the neonate will also utilize the peptide. H u m a n infants metabolize peptides present in protein hydrolysates administered parenterally (36,39).…”

Section: Discussionmentioning

confidence: 99%

“…peptide utilization is nearly equal to that of infused amino acids once products of the Maillard reaction are eliminated from the parenteral solutions (I I. 36,39). Preliminary studies (36) indicated good utilization of L-alanyl-I.-tyrosine as a tyrosine source in adult rats when administered at 0.5 mmole/kg/day either by ip injection or as part of a total parenteral nutrition regimen.…”

Section: Speculationmentioning

confidence: 99%

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L-Alanyl-L-Tyrosine As A Tyrosine Source During Total Parenteral Nutrition. Infusion at 0.5 and 2 mmoles/kg/day in Adult Rats

Daabees

Stegink

1979

Pediatr Res

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SummaryTyrosine peptides, such as L-alanyl-L-tyrosine, have excellent solubility and are potential sources of iv tyrosine. Infusion of Lalanyl-1.-U-'T-tyrosine as part of a total parenteral nutrition reginien in the rat at a level of 0.5 mmole/kg/day resulted in rapid labeling of tissue tyrosine pools, production of I4CO2, incorporation of 14C-labeled tyrosine into protein, and minimal urinary losses (7.7%). Plasnla tyrosine levels, however, remained at fasting. Infusion of I.-alanyl-L-tyrosine at 2 mmole/kg/day increased plasnia tyrosine above fasting levels and maintained tissue tyrosine at levels seen in orally fed control animals without increasing the percent lost in urine (5.5'10). Rapid utilization of L-alanyl-L-tyrosine was noted at both infusion levels with no accumulation of peptide noted in plasma. Plasma and tissue free tyrosine pools were rapidly labeled, as was tissue protein. Radioactivity incorporated in tissue protein was shown to be tyrosine after acid hyrolysis. SpeculationTyrosine content of parenteral solutions is limited by poor tyrosine solubility. Tyrosine peptides are soluble and are well utilized during iv feeding of adult rats. This suggests that tyrosine peptides are a reasonable source for supplying the tyrosine requirements of iv fed infants.Cystine and tyrosine are essential amino acids for some premature infants (19,33,41). Both amino acids have limited solubility, and cannot be added to total parenteral nutrition solutions in quantities sufficient to meet the infants requirements. The absence of these amino acids results in depresed cystine and tyrosine levels in infants infused with such solutions (30,35,38).Soluble peptides of cystine and tyrosine are potential sources for adding these amino acids to parenteral solutions (36). Although some studies suggested that peptide nitrogen is not well utilized during parenteral nutrition (7-1 1, 13, 16, 21, 23). peptide utilization is nearly equal to that of infused amino acids once products of the Maillard reaction are eliminated from the parenteral solutions (I I. 36, 39). Preliminary studies (36) indicated good utilization of L-alanyl-I.-tyrosine as a tyrosine source in adult rats when administered at 0.5 mmole/kg/day either by ip injection or as part of a total parenteral nutrition regimen. The peptide was utilized as a tyrosine source for protein synthesis, as evidenced by incorporation of tyrosine into tissue protein, and for energy production, as evidenced by rapid conversion to carbon dioxide. However, plasma tyrosine levels remained in the fasting range and 7.7% of peptide tyrosine was lost in the urine. The present study compares infusion of I--alanyl-L-tyrosine at 0.5 and 2.0 mmole/kg/day as part of a parenteral nutrition regimen in adult rats to determine whether: I) good utilization occurs at higher peptide infusion levels; 2) plasma tyrosine levels can be increased above fasting levels; and 3) urinary losses of tyrosine will increase at higher infusion levels. MATERIALS AND METIIODSI.-Alanyl-L-tyrosine and L-alanyl-L-U-14C-...

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Section: Discussionmentioning

confidence: 99%

Section: Speculationmentioning

confidence: 99%

L-Alanyl-L-Tyrosine As A Tyrosine Source During Total Parenteral Nutrition. Infusion at 0.5 and 2 mmoles/kg/day in Adult Rats

Daabees

Stegink

1979

Pediatr Res

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“…Heat sterilization of parenteral solutions containing protein hydrolysates along with glucose results in the formation of glucose-amino acid complexes. The intravenous administration of heat-sterilized parenteral nutrition formulas has been associated with mild dehydration in infants (Stegink et al, 1974) and with excessive urinary zinc excretion in both infants and adults (Freeman et al, 1975;Stegink et al, 1975). When these formulae were administered to the pregnant rhesus monkey, the sugar-amino acid complexes accumulated in the maternal plasma and were transported to the fetal circulation.…”

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Absorption and metabolism of lysine Maillard products in relation to utilization of L-lysine

Sherr¹,

Lee²,

Jelesciewicz³

1989

J. Agric. Food Chem.

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Die Maillard‐Reaktion in Lebensmitteln und im menschlichen Körper – neue Ergebnisse zu Chemie, Biochemie und Medizin

1990

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Die beim Kochen, Backen und Konservieren stattfindenden Reaktionen sind von großer Bedeutung für den Geruch, den Geschmack und das Aussehen von Lebensmitteln. In neueren Untersuchungen wurde festgestellt, daß derartige Reaktionen auch zu Nährwertminderungen und zur Bildung von toxischen Verbindungen führen können. Ein wichtiges Beispiel ist die als nichtenzymatische Bräunung oder Maillard‐Reaktion bekannte, sehr komplex ablaufende Reaktion zwischen reduzierenden Zuckern und freien Aminogruppen von Aminosäuren oder Proteinen. Einen prinzipiell neuen Aspekt bekam die Maillard‐Reaktion, als bekannt wurde, daß sie auch im menschlichen Körper abläuft. Allgemein gilt, daß um so größere Mengen an Maillard‐Produkten gefunden werden, je länger die Halbwertszeit des beteiligten Proteins ist, d. h. je „älter”︁ das Protein im Körper wird, und je höher die Glucosekonzentration, z. B. bei Diabetikern, ist. Da viele Diabetes‐Spätschäden einer frühzeitigen Alterung ähneln, wäre es denkbar, daß die Glucose durch Reaktion mit Proteinen das langsam fortschreitende Altern mitverursacht.

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Sugar-Amino Acid Complexes in Parenteral Alimentation

Cited by 10 publications

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L-Alanyl-L-Tyrosine As A Tyrosine Source During Total Parenteral Nutrition. Infusion at 0.5 and 2 mmoles/kg/day in Adult Rats

L-Alanyl-L-Tyrosine As A Tyrosine Source During Total Parenteral Nutrition. Infusion at 0.5 and 2 mmoles/kg/day in Adult Rats

Absorption and metabolism of lysine Maillard products in relation to utilization of L-lysine

Die Maillard‐Reaktion in Lebensmitteln und im menschlichen Körper – neue Ergebnisse zu Chemie, Biochemie und Medizin

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