[Studies of solutions with various branched-chain amino acid contents on protein metabolism in the postoperative period. 1. A 15N tracer kinetic animal model for evaluating the effect of parenteral amino acid administration on nitrogen metabolism].

We were able to estimate nitrogen or protein metabolism on the basis of a 15N metabolic model that delivered a high amount of data during a parenteral nutrition period over 72 h. We describe the basic principles of the necessary N or 15N-analyses in blood, as well as in sera, in urine, in tissues of selected organs and in hepatocytes. This 15N-metabolic model allows the estimation of the utilization of amino acid infusion solutions. Because of the great similarity of parameters of the N or protein turnover between man and pig it is possible to provide relevant information for the clinical practice regarding amino acid infusion solutions.