Diabetes enhances activity of alanine transport in liver plasma membrane vesicles.
Diabetes enhances activity of alanine transport in liver plasma membrane vesicles.
复制标题
糖尿病增强肝质膜囊泡中丙氨酸转运的活性。
DOI：
10.1152/ajpendo.1985.248.5.e581
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
Barrett,E
中科院分区：
文献类型：
--
作者：
Rosenthal,NR;Jacob,R;Barrett,E
本研究分别从四氧嘧啶诱导的糖尿病大鼠和对照大鼠的肝脏制备了质膜囊泡，并测定了两组丙氨酸转运的底物特异性和动力学特性。在生理丙氨酸浓度（100微米）下，与对照动物相比，糖尿病动物钠依赖性丙氨酸摄取增加了三倍（0.31 +/- 0.04 vs 0.11 +/- 0.01 nmol X mg蛋白-1 X 10 s-1）。这种加速的内流对应于糖尿病患者丙氨酸运输的Vmax比对照组增加了三到四倍（7.1 +/- 2.1 vs. 1.6 +/- 0.2 nmol X mg protein-1 X 10 s-1, P < 0.05），而丙氨酸摄取的Km不变（2.8 +/- 1.2 vs. 1.4 +/- 0.1 mM）。其他中性氨基酸（20 mM）对两组丙氨酸运输的抑制程度相似。钠依赖性谷氨酰胺内流（100微米）在糖尿病组和对照组相似（分别为0.17 +/- 0.03和0.14 +/- 0.02 nmol X mg蛋白-1 X 10 s-1）。在两组中，在基本相同的钠浓度（约40 mM）下，获得了22Na进入囊泡的初始速度（80 mM）和丙氨酸运输的半最大刺激。（摘要删节250字）
In the present study plasma membrane vesicles were prepared from livers of control and alloxan-induced diabetic rats and the substrate specificity and kinetic characteristics of alanine transport determined in both groups. Sodium-dependent alanine uptake at physiological alanine concentrations (100 microM) was enhanced threefold in diabetic as compared with control animals (0.31 +/- 0.04 vs. 0.11 +/- 0.01 nmol X mg protein-1 X 10 s-1). This accelerated influx corresponded to a three- to fourfold increase in the Vmax of alanine transport in diabetic versus control group (7.1 +/- 2.1 vs. 1.6 +/- 0.2 nmol X mg protein-1 X 10 s-1, P less than 0.05), whereas the Km of alanine uptake was unchanged (2.8 +/- 1.2 vs. 1.4 +/- 0.1 mM). Other neutral amino acids (20 mM) inhibited alanine transport to a similar degree in both groups. The sodium-dependent influx of glutamine (100 microM) was similar in diabetic and control groups (0.17 +/- 0.03 and 0.14 +/- 0.02 nmol X mg protein-1 X 10 s-1, respectively). The initial velocity of 22Na uptake (80 mM) into vesicles and half-maximal stimulation of alanine transport was achieved at essentially identical sodium concentrations (approximately 40 mM) in both groups.(ABSTRACT TRUNCATED AT 250 WORDS)