Selective up-regulation of system a transporter mRNA in diabetic liver.
Selective up-regulation of system a transporter mRNA in diabetic liver.
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DOI：
10.1006/bbrc.2001.6281
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发表时间：
2002-01
影响因子：
3.1
通讯作者：
H. Varoqui;J. Erickson
中科院分区：
文献类型：
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作者：
H. Varoqui;J. Erickson
系统A对丙氨酸的转运是肝脏合成葡萄糖的重要碳源。在这里，我们表明，mRNA编码的大鼠系统A转运蛋白（SAT 2）的普遍表达的亚型显着增加，在肝脏链脲佐菌素诱导的糖尿病。SAT2 mRNA的这种增加在肝硬化门脉周围肝细胞和中央静脉周围的肝细胞中得到加强。SAT 3是肝脏中存在的更丰富的系统A mRNA同种型，仅限于静脉周围肝细胞，并且在该处理后也增加，但程度远低于SAT 2 mRNA。SN1是一种在静脉周围和门静脉周围肝细胞中表达的丰富的系统N mRNA亚型，不受链脲佐菌素治疗的影响。药理剂量的胰高血糖素也增加了肝脏中的SAT 2和SAT 3 mRNA水平，而SN 1 mRNA水平保持不受影响。这些结果表明，在实验诱导的糖尿病或胰高血糖素治疗后在肝脏中观察到的系统A活性的增加是由于编码系统A转运蛋白的mRNA的选择性增加。
The transport of alanine by system A is an important source of carbons for the synthesis of glucose in the liver. Here, we show that the mRNA encoding the ubiquitously expressed isoform of the rat system A transporter (SAT2) is dramatically increased in liver following streptozotocin-induced diabetes. This increase in SAT2 mRNA is intensified in the gluconeogenic periportal hepatocytes and also in hepatocytes surrounding the central vein. SAT3, the more abundant system A mRNA isoform present in liver, is restricted to perivenous hepatocytes and is also increased following this treatment but to a much lesser extent than SAT2 mRNA. SN1, an abundant system N mRNA isoform expressed in both perivenous and periportal hepatocytes, is not affected by streptozotocin treatment. A pharmacological dose of glucagon also increased both SAT2 and SAT3 mRNA levels in liver while SN1 mRNA levels remained unaffected. These results indicate that the increase in system A activity observed in liver following experimentally induced diabetes or glucagon treatment is due to the selective increase in mRNAs encoding system A transporters.