Lavoie Jean-Claude, Rouleau Thérèse, Truttmann Anita C, Chessex Philippe
Research Centre and Neonatal Service, Hĵpital Ste-Justine, Montreal, Que, Canada.
Free Radic Res. 2002 Aug;36(8):811-7. doi: 10.1080/1071576021000005230.
In view of the functional capacity of glutathione synthesis in premature infants, and because the availability of cysteine is one the rate limiting steps in glutathione synthesis, we hypothesized that the low glutathione levels in premature infants may be due to immaturity of the active cellular uptake of cysteine.
To document in cells from newborn infants the effect of maturity and gender on cysteine uptake and consequently on glutathione levels.
Incorporation of L-[35S] cysteine was measured in leukocytes from cord blood and from tracheal aspirates (TAC) of newborn infants of varying (gestational as well as postnatal) ages and gender. Cysteine uptake was correlated with glutathione in TAC.
The maturity of newborn girls positively influences cysteine uptake, which is responsible for 78% of the variation in their glutathione content. However, in newborn boys, gestational and postnatal ages did not influence the cysteine uptake.
Cysteine uptake appears to be the limiting step explaining the reported gender-related differences in glutathione as well as the low levels of this central antioxidant found in premature infants. The immature cysteine uptake found in cells from premature infants raises questions about the bioavailability of this conditionally essential amino acid in regimens of parenteral nutrition for human neonates.
鉴于早产儿谷胱甘肽合成的功能能力，且由于半胱氨酸的可用性是谷胱甘肽合成的限速步骤之一，我们推测早产儿谷胱甘肽水平低可能是由于细胞对半胱氨酸的主动摄取不成熟所致。
记录新生儿细胞中成熟度和性别对半胱氨酸摄取以及谷胱甘肽水平的影响。
测量不同（胎龄及出生后）年龄和性别的新生儿脐带血及气管吸出物（TAC）白细胞中L-[35S]半胱氨酸的掺入情况。TAC中的半胱氨酸摄取与谷胱甘肽相关。
新生女婴的成熟度对半胱氨酸摄取有正向影响，这占其谷胱甘肽含量变化的78%。然而，在新生男婴中，胎龄和出生后年龄并未影响半胱氨酸摄取。
半胱氨酸摄取似乎是解释所报道的谷胱甘肽性别相关差异以及早产儿中这种核心抗氧化剂水平低的限制步骤。早产儿细胞中半胱氨酸摄取不成熟引发了关于这种条件必需氨基酸在人类新生儿肠外营养方案中的生物利用度的问题。
