[Investigations on the utilization of parenterally administered amino acids by premature and small-for-dates neonates. I. Free amino acids in the blood of premature and small-for dates neonates (author's transl)].

The fasting levels of free amino acids were determined in the serum of 23 premature and 7 small-for-dates newborns during the first 4 weeks of life. This was done by ion-exchange chromatography after ultrafiltration of the serum, which allowed quantification. Differences were recognized in regards to age, and nutritional state: 1. Small-for-dates newborns at term showed significantly lower asparagine and glycine levels when compared to hypotrophic prematures. 2. Leucine was lower in male than in female prematures. 3. Leucine and phenylalanine were lower in hypotrophic than in eutrophic prematures. 4. Nearly all investigated fasting amino acid levels were highest in the 3rd week of life. A decrease was observed during the 4th week of life. Threonine, Proline, Alanine, Valine, Isoleucine, Lysine and Arginine were significantly higher in the 3rd compared to the 1st week.