Glutamine-glutamate exchange between placenta and fetal liver.
Glutamine-glutamate exchange between placenta and fetal liver.
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胎盘和胎儿肝脏之间的谷氨酰胺-谷氨酸交换。
DOI：
10.1152/ajpendo.1995.268.4.e705
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发表时间：
1995
期刊：
影响因子：
--
通讯作者：
Meschia,G
中科院分区：
文献类型：
--
作者：
Vaughn,PR;Lobo,C;Battaglia,FC;Fennessey,PV;Wilkening,RB;Meschia,G
通过将L-[1,2-13C2]谷氨酰胺注入六只长期插管以采集脐带和肝脏循环样本的胎羊体内，探索了谷氨酰胺通过与谷氨酸的相互转化在胎盘和胎儿肝脏之间穿梭氮的假设。胎儿血浆谷氨酰胺处理率为 19.9 +/- 1.3 mumol.min-1.kg fetus-1。从胎盘进入的谷氨酰胺约占胎儿血浆中总谷氨酰胺进入率的60%。谷氨酰胺被胎儿肝脏吸收，所吸收的谷氨酰胺的45.3+/-7.9%以谷氨酸形式释放。胎儿肝脏释放大量谷氨酸，流经左肝叶的血液中血浆谷氨酸浓度增加六倍以及肝脏谷氨酸输出与 O2 摄取摩尔比为 0.149 +/- 0.013 就证明了这一点。结合之前对胎儿谷氨酸代谢的研究，这些数据表明，进入胎儿循环的谷氨酰胺被胎儿肝脏以大约3-4 mumol.min-1.kg fetus-1的速率转化为谷氨酸。
The hypothesis that glutamine shuttles nitrogen between placenta and fetal liver via interconversion with glutamate was explored by infusing L-[1,2-13C2]glutamine in six fetal sheep chronically catheterized for sampling of the umbilical and hepatic circulations. Fetal plasma glutamine disposal rate was 19.9 +/- 1.3 mumol.min-1.kg fetus-1. Entry of glutamine from the placenta accounted for approximately 60% of the total glutamine entry rate in fetal plasma. Glutamine was taken up by fetal liver, and 45.3 +/- 7.9% of the glutamine taken up was released as glutamate. The fetal liver released large quantities of glutamate, as evidenced by a sixfold increase in plasma glutamate concentration in the blood flowing through the left hepatic lobe and a hepatic glutamate output-to-O2 uptake molar ratio of 0.149 +/- 0.013. In conjunction with a previous study of fetal glutamate metabolism, these data demonstrate that glutamine entering the fetal circulation is converted to glutamate by the fetal liver at a rate of approximately 3-4 mumol.min-1.kg fetus-1.