Increased concentrations of tyrosine and phenylalanine in the cerebrospinal fluid as a possible reflection of related changes of the brain tissue in newborns with intra-uterine growth retardation.

ABSTRACT

Plasma and cerebrospinal fluid concentrations of tyrosine and phenylalanine were measured fluorometrically in human term neonates appropriate for gestational age and in neonates small for gestational age with severe intra-uterine growth retardation of Type II. The intra-uterine retarded newborns showed significant differences of both plasma and cerebrospinal fluid tyrosine levels as compared with the non-retarded newborns the mean plasma and cerebrospinal fluid tyrosine were determined to be 2.0 and 2.5 times, respectively, higher in the retarded group. The mean cerebrospinal fluid phenylalanine content was also increased in these newborns. The findings may reflect cellular disturbances of the tyrosine metabolization in the developing brain as it can also be found in experimental intra-uterine growth retarded animals.