Sheard N F, Zeisel S H
Pediatr Res. 1986 Aug;20(8):768-72. doi: 10.1203/00006450-198608000-00014.
We studied choline uptake by slices of adult and 10-day-old rat intestine which were exposed on their mucosal surface to radiolabeled choline. Both neonatal and adult intestine transported choline. Choline uptake was observed in duodenum, jejunum, ileum, and colon of the adult rat. In the small intestine, choline uptake consisted of two components: a saturable and a nonsaturable process. The kinetic variables for saturable transport (Km, Vmax) were not significantly different in adult and neonatal small intestine. Some of the transported choline was converted to phosphatidylcholine, glycerophosphocholine, phosphocholine, and betaine. However, most of the transported choline (79-85%) was not metabolized within the intestinal slice during a 15-min period. We conclude that the capacity for choline transport in the rat small intestine is present early in neonatal life. The characteristics of this transport mechanism for choline are similar in the neonate and in the adult small intestine. Neonates should therefore be able to absorb the large amounts of unesterified choline that are present in milk.
我们研究了成年大鼠和10日龄大鼠的肠切片对胆碱的摄取情况，这些肠切片的黏膜表面暴露于放射性标记的胆碱。新生大鼠和成年大鼠的肠道均能转运胆碱。在成年大鼠的十二指肠、空肠、回肠和结肠中均观察到胆碱摄取。在小肠中，胆碱摄取由两个部分组成：一个可饱和过程和一个非饱和过程。成年和新生大鼠小肠中可饱和转运的动力学变量（Km、Vmax）无显著差异。一些转运的胆碱被转化为磷脂酰胆碱、甘油磷酸胆碱、磷酸胆碱和甜菜碱。然而，在15分钟内，大部分转运的胆碱（79 - 85%）在肠切片内未被代谢。我们得出结论，大鼠小肠中胆碱转运能力在新生儿期早期就已存在。新生儿和成年大鼠小肠中这种胆碱转运机制的特征相似。因此，新生儿应该能够吸收乳汁中存在的大量未酯化胆碱。
