Sena A, Ferret-Sena V, Sarliève L L, Tholey G
Departamento de Bioquimica, Faculdade de Ciências Médicas, Univesidade Nova de Lisboa, Portugal.
J Neurosci Res. 1988;20(2):189-94. doi: 10.1002/jnr.490200207.
The effect of physiological concentrations of insulin (2 and 20 ng/ml) on glutamine synthetase (GS) and glutamate dehydrogenase (GDH) activities were compared in mouse and chick glial cells in culture. Addition of insulin to serum-containing medium increased the level of GS and GDH activities in glial cells prepared from 14-15-day-old embryonic mice. A similar but less pronounced effect was observed with glia derived from newborn mouse brain. In absence of serum, addition of insulin had no effect on the tested enzymes. The effects of insulin on enzymatic activities of glial cells from 14-15-day-old embryonic chick brain hemispheres were, in contrast, quite different. A significant decrease of GS activity was induced by the hormone, only in the absence of serum. Conversely, the presence of serum enhanced an inhibitory effect of insulin toward chick GDH. The different effects of insulin and the different serum dependence observed for the mammalian and the avian model could reflect fundamental chemical differences between both species as indicated by immunoelectrophoretic analysis. However, it can be concluded that insulin may be a physiological factor regulating glial maturation and amino acid neurotransmitter metabolism in the central nervous system.
在培养的小鼠和鸡神经胶质细胞中，比较了生理浓度胰岛素（2和20纳克/毫升）对谷氨酰胺合成酶（GS）和谷氨酸脱氢酶（GDH）活性的影响。向含血清培养基中添加胰岛素可增加从14 - 15日龄胚胎小鼠制备的神经胶质细胞中GS和GDH的活性水平。在源自新生小鼠脑的神经胶质细胞中观察到类似但不太明显的效应。在无血清情况下，添加胰岛素对所测试的酶没有影响。相比之下，胰岛素对14 - 15日龄胚胎鸡脑半球神经胶质细胞酶活性的影响则大不相同。仅在无血清时，该激素可诱导GS活性显著降低。相反，血清的存在增强了胰岛素对鸡GDH的抑制作用。胰岛素的不同效应以及在哺乳动物和禽类模型中观察到的不同血清依赖性，可能反映了两种物种之间的基本化学差异，免疫电泳分析表明了这一点。然而，可以得出结论，胰岛素可能是调节中枢神经系统中神经胶质细胞成熟和氨基酸神经递质代谢的生理因子。
