Shiota M, Hiramatsu M, Fujimoto Y, Moriyama M, Kimura K, Ohta M, Sugano T
Department of Veterinary Physiology, College of Agriculture, University of Osaka Prefecture, Japan.
Arch Biochem Biophys. 1994 Feb 1;308(2):349-56. doi: 10.1006/abbi.1994.1050.
The capacity of the malate-aspartate shuttle was evaluated in periportal (PP-H) and perivenous subfraction of rat hepatocytes (PV-H). The rate of glutamine production from alanine was 34-fold higher in PV-H than in PP-H. Statistically significant differences between PP-H and PV-H were found for the activities of lactate dehydrogenase and pyruvate kinase but not for the activities of NAD(+)-malate dehydrogenase, aspartate aminotransferase, and mitochondrial alanine aminotransferase. The rate of glucose production from sorbitol and the rate of ethanol utilization were higher in PP-H than in PV-H. In the presence of phenazine methosulfate (PMS), the increments in these rates were significantly greater in PV-H than in PP-H. The capacity of malate-aspartate shuttle in the presence of alanine was significantly higher in PP-H than in PV-H but in the presence of asparagine was similar in PP-H and PV-H. The results suggest that the capacity of malate-aspartate shuttle distributes heterogeneously along liver lobules with the dominance in periportal zone and that the difference of the capacity may result from the difference in the transport of aspartate across the mitochondrial membrane.
在大鼠肝细胞的门静脉周围亚组分（PP-H）和肝静脉周围亚组分（PV-H）中评估了苹果酸-天冬氨酸穿梭的能力。PV-H中由丙氨酸生成谷氨酰胺的速率比PP-H中高34倍。PP-H和PV-H之间在乳酸脱氢酶和丙酮酸激酶的活性上存在统计学显著差异，但在NAD(+)-苹果酸脱氢酶、天冬氨酸转氨酶和线粒体丙氨酸转氨酶的活性上未发现差异。PP-H中由山梨醇生成葡萄糖的速率和乙醇利用速率比PV-H中高。在存在吩嗪硫酸甲酯（PMS）的情况下，PV-H中这些速率的增加显著大于PP-H。在存在丙氨酸的情况下，PP-H中苹果酸-天冬氨酸穿梭的能力显著高于PV-H，但在存在天冬酰胺的情况下，PP-H和PV-H中的能力相似。结果表明，苹果酸-天冬氨酸穿梭的能力沿肝小叶呈异质性分布，在门静脉周围区占优势，且这种能力的差异可能源于天冬氨酸跨线粒体膜转运的差异。
