The effects of a new amino-acid dipeptide solution on nitrogen balance and humoral growth factors in the postoperative state in man

27 patients admitted for elective abdominal surgery were allocated to receive postoperative total parenteral nutrition supplemented with glutamine (glycyl-glutamine) and tyrosine (glycyl-tyrosine) containing dipeptides (DP-Gln 20; 0.16 g glutamine/kg BW/24 h) or isonitrogenous Vamin 18 for 5 days. The aim was to evaluate safety and effects on short-life plasma proteins, nitrogen balance, 3-methylhistidine excretion and alimentary growth factors in plasma. No differences in transthyretin or retinol binding protein levels, nitrogen balance or 3-methylhistidine excretion were found in patients receiving DP-Gln 20 compared to Vamin 18. There were higher plasma levels of peptide YY in the dipeptide group 5 days after surgery (p < 0.05). A correlation between insulin levels and nitrogen balance was found only in DP-Gln 20 treated patients day 6 (r = 0.91, p < 0.01). DP-Gln 20 is a glutamine dipeptide (Gly-Gln) containing amino acid solution which is considered safe in the postoperative state in man. No beneficial effects on whole body protein metabolism were found by adding DP-Gln 20 to total parenteral nutrition.