The ratio of the plasma concentration of glycine, serine, glutamine and taurine to the concentration of leucine, isoleucine, valine and methionine in the newborn infant has been studied by WHITEHEAD’S method using paper chromatography. The mean amino acid ratio in the umbilical vein is significantly lower than in the maternal circulation (1.4 ±0.20 versus 1.7 ±0.27). After birth a rapid and opposite change in the levels of these amino acids causes a rise in their ratio. The highest value is attained between 18 and 30 h postnatally. After the second day of extrauterine life the total concentration of glycine, serine, glutamine and taurine falls and that of leucine, isoleucine, valine and methionine rises, resulting in a lowering in their ratio. These changcs in the plasma free amino acid pattern represent a physiological response occurring in the early postnatal period of the human infant.
ASJC Scopus subject areas
- Pediatrics, Perinatology, and Child Health
- Developmental Biology