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Effects of phenylalanine loading on protein synthesis in the fetal heart and brain of rat: an experimental approach to maternal phenylketonuria
Author(s) -
Okano Y.,
Chow I. Z.,
Isshiki G.,
Inoue A.,
Oura T.
Publication year - 1986
Publication title -
journal of inherited metabolic disease
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.462
H-Index - 102
eISSN - 1573-2665
pISSN - 0141-8955
DOI - 10.1007/bf01813896
Subject(s) - phenylalanine , hyperphenylalaninemia , fetus , medicine , placenta , leucine , endocrinology , amino acid , urea , phenylketonurias , chemistry , pregnancy , biology , biochemistry , genetics
Pregnant rats were loaded with l ‐phenylalanine, and the distributions of [ 14 C]leucine and [ 14 C]urea into fetal plasma and tissues were examined. Uptake of [ 14 C]leucine into the supernatant and protein fractions of fetal plasma and tissues was low in the rats loaded with phenylalanine. In contrast, [ 14 C]urea was distributed identically in both groups, indicating that maternal hyperphenylalaninemia did not affect blood flow across the placenta. Administration of phenylalanine and p ‐chlorophenylalanine produced amino acid imbalance in fetal tissues. Along with these changes, polysomes of the affected fetal heart and brain disaggregated without changes in the ribonuclease activity. These results indicate that high phenylalanine levels in maternal plasma disturb the active transport of amino acids across the placenta, causing an amino acid imbalance and disaggregation of polysomes in fetal heart and brain. These changes may contribute to the congenital heart disease and mental retardation of maternal phenylketonuria.