摘要
目的:谷氨酰胺是肠道细胞的主要氧化燃料,必须通过载体的转运才能进入细胞内。研究IEC-6细胞膜上分布的谷氨酰胺载体种类及其功能。方法:体外培养肠黏膜上皮细胞株IEC-6,检测细胞膜上不同谷氨酰胺载体(ASCT2、SN1、SN2、ATA1、ATA2、LAT1、LAT2)的mRNA;检测载体ASCT2蛋白;测定不同载体对同位素标记谷氨酰胺的转运特性。结果:在IEC-6细胞膜上载体ASCT2、SN1、ATA1、LAT1、LAT2的mRNA均得以表达。细胞外缓冲液中Na+存在时,[3H]-谷氨酰胺摄取率为(164.07±37.94)fmol/(mg protein.10 min);Na+不存在时,[3H]-谷胺酰胺摄取率为(58.71±10.51)fmol/(mg protein.10 min);饱和剂量甲氨基异丁酸(methylamino-isobutyric acid,MeAIB)阻断A类载体后,[3H]-谷氨酰胺摄取率为(81.02±19.59)fmol/(mg protein.10 min)。结论:在IEC-6细胞膜上可能存在载体ASCT2、SN1、ATA1、LAT1、LAT2;Na+依赖性氨基酸载体起主要作用(约64.22%),其中A类载体占50.62%,非A类载体占13.60%,非Na+依赖载体起次要作用(35.78%)
Objective：Glutamine is the main oxidative fuel of the enterocyte which enters the enterocyte primarily via amino acid transporters. The aim of the test was to study the distributions and functions of glutamine transporters in IEC-6 cell line. Methods：The rat intestinal epithelial cell line （IEC-6） was incubated in vitro. The mRNA expression of different glutamine transporters, protein expression of system ASCT2, and the [^3H]-L-glutamine uptake were measured. Results：The mRNA of system ASCT2, SN1, ATA1, LAT1, LAT2 was expressed and the protein expression of ASCT2 was also validated in IECu6. In Na^＋-containing buffer, the velocity of Na^＋-dependent glutamine uptake was （164.07 ± 37.94） fmol/（mg protein·10min）. In Na^＋ -free buffer, the velocity of glutamine uptake was （58.71 ± 10.51 ）fmol/（mg protein · 10 min）. With the saturate dosage of MeAIB, the velocity of glutamine uptake was （81.02 ± 19.59） fmol/（mg protein·10 rain）. Conclusion：There may be five kinds of glutamine transporters （ASCT2, SNI, ATA1, LAT1, and LAT2） in IEC-6 cell. The Na^＋-dependent transporter was the major contributor （64.22%） to glutamine total uptake in IEC-6. The contributions of system A and the remainder were 50.62% and 13.60%, respectively. The Na^＋-independent transporter was the lesser contributor（35.78%）.
出处
《医学研究生学报》
CAS
2009年第7期677-681,共5页
Journal of Medical Postgraduates
基金
国家自然科学基金资助项目(批准号:30271263)
