White F P, Hertz L
Neurochem Res. 1981 Apr;6(4):353-64. doi: 10.1007/BF00963850.
Protein synthesis, measured as leucine incorporation into acid-precipitable proteins, was determined in astrocytes in primary cultures obtained from the cerebral hemispheres of newborn mice. As can be expected for eucaryotic, ribosomal protein synthesis, the incorporation was almost completely inhibited by cycloheximide (0.01 mM), but unaffected by chloramphenicol (0.03 mM). The rate of synthesis, measured during exposure to a high (0.8 mM) concentration of leucine was 5.4 nmol/hr/mg protein in mature (i.e., at least 4-week-old) cultures. This value is at least twice as high as the protein synthesis rates reported for the adult brain in vivo, suggesting that a very considerable part of the protein synthesis in the adult brain may take place in astrocytes. The molecular weight distribution of the synthesized proteins was determined by polyacrylamide gel electrophoresis, demonstrating synthesis of at least 50 different polypeptides, ranging in molecular weight between 190,000 and 27,000 daltons. The pattern of the synthesized proteins underwent considerable alteration with age in young cultures in which the total content of protein was still increasing, but it was remarkably stable after the age of two weeks. Exposure to dibutyryl cyclic AMP, which is known to alter morphology, content of glial fibrillary acidic protein (GFA), and activities of certain enzymes in the cultures in the cultured astrocytes, caused marked alterations in the pattern of the synthesized proteins.
蛋白质合成通过测定亮氨酸掺入酸沉淀蛋白的量来确定，该实验在取自新生小鼠大脑半球的原代培养星形胶质细胞中进行。正如真核生物核糖体蛋白合成所预期的那样，环己酰亚胺（0.01 mM）几乎完全抑制了掺入，但氯霉素（0.03 mM）对其无影响。在暴露于高浓度（0.8 mM）亮氨酸期间测得的成熟（即至少4周龄）培养物中的合成速率为5.4 nmol/小时/毫克蛋白。该值至少是成年大脑体内报道的蛋白质合成速率的两倍，这表明成年大脑中相当一部分蛋白质合成可能发生在星形胶质细胞中。通过聚丙烯酰胺凝胶电泳确定合成蛋白质的分子量分布，结果表明至少合成了50种不同的多肽，分子量在190,000至27,000道尔顿之间。在蛋白质总量仍在增加的年轻培养物中，合成蛋白质的模式随年龄发生了相当大的变化，但在两周龄后则非常稳定。已知二丁酰环磷腺苷可改变培养星形胶质细胞的形态、胶质纤维酸性蛋白（GFA）的含量以及某些酶的活性，暴露于二丁酰环磷腺苷会导致合成蛋白质的模式发生显著变化。
