足月儿和早产儿生命早期5-L-氧代脯氨酸（焦谷氨酸）的尿排泄情况。
Urinary excretion of 5-L-oxoproline (pyroglutamic acid) during early life in term and preterm infants.
作者信息
Jackson A A, Persaud C, Hall M, Smith S, Evans N, Rutter N
机构信息
Institute of Human Nutrition, University of Southampton.
出版信息
Arch Dis Child Fetal Neonatal Ed. 1997 May;76(3):F152-7. doi: 10.1136/fn.76.3.f152.
Urinary 5-L-oxoproline was measured in term and preterm infants from shortly after birth until 6 weeks of postnatal age to determine their ability to synthesise glycine. In term infants the excretion was five to 10 times that seen in normal adults, increasing from 105 mumol/mmol creatinine in the first 72 hours after birth to 170 mumol/mmol creatinine at 6 weeks of age. There was a significant inverse linear correlation between the excretion of 5-L-oxoproline and length of gestation or birthweight. By 6 weeks of age there was no longer a significant difference in 5-L-oxoproline between term and preterm infants. There was no difference in the excretion of 5-L-oxoproline between boys and girls, or between infants fed on human milk or an artificial formula. If, in part, variability in the excretion of 5-L-oxoproline is determined by the extent to which the endogenous formation of glycine is adequate, then glycine formation may be marginal during early life, more so in preterm than in term infants, providing additional evidence that glycine is a conditionally essential amino acid in the neonate.
测定了足月儿和早产儿从出生后不久至出生后6周的尿中5-L-氧代脯氨酸水平，以确定他们合成甘氨酸的能力。足月儿的排泄量是正常成年人的五到十倍，从出生后最初72小时的105微摩尔/毫摩尔肌酐增加到6周龄时的170微摩尔/毫摩尔肌酐。5-L-氧代脯氨酸的排泄量与妊娠时长或出生体重之间存在显著的负线性相关。到6周龄时，足月儿和早产儿之间的5-L-氧代脯氨酸水平不再有显著差异。男孩和女孩之间，以及母乳喂养或人工配方奶喂养的婴儿之间，5-L-氧代脯氨酸的排泄量没有差异。如果5-L-氧代脯氨酸排泄量的部分变异性取决于内源性甘氨酸形成充足的程度，那么在生命早期，甘氨酸的形成可能处于边缘状态，早产儿比足月儿更甚，这进一步证明了甘氨酸是新生儿的一种条件必需氨基酸。
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