[The human utilization of orally administered 15N-glycine]

In 7 convalescent patients we studied utilisation of a single dose of 15N-labelled glycine. In intervals we estimated total-N, urea-N, NH3-N and their 15N-abundances (urine). The following results were obtained. The peak of ammonium-15N appeared 25 minutes earlier than the peak of urea-15 N. The cumulative elimination of total-15N amounted to 25% of uptake after 24 hours and to 34.4% after 6 days. 12 hours after application 53% of the total amount, excreted within 6 days, were already eliminated. 24 hours after administration 80% of total-15N was urea-15N and 2.8% NH3-15N. Further we found correlations between N-balance (N-application minus excretion) and elimination of 15N-urea: If N-balance got more negative, the amount of cumulative elimination, the portion of urea-15N to total-15N and the percentage of elimination after 12 hours related to 6 days were elevated. That means that in stress condition utilisation of glycine to urea is higher and accelerated. The model seems acceptable, to get information concerning metabolic situation in a simple way.