Khelil M, Rolland B, Fages C, Tardy M
INSERM U 282, Hôpital Henri Mondor, Créteil, France.
Glia. 1990;3(1):75-80. doi: 10.1002/glia.440030110.
Astroglial cells from mouse cerebral hemispheres, cerebellum, olfactory bulbs, and medulla oblongata were grown in the presence of either hormones (hydrocortisone, insulin) or cell second messengers (dBcAMP, dBcGMP). Glutamine synthetase (GS) specific activity, GS protein level, and GS translation were investigated under the effect of these factors. Hydrocortisone produced a simultaneous increase in GS translation, GS level, and activity. This increase was observed in the astrocytes cultured from the four brain areas but at a variable magnitude depending on the area. The hydrocortisone effect appeared at the transcriptional level. Inversely, insulin decreased both the GS activity and the in vitro translated GS. This effect was seen only in the olfactory bulbs and the medulla. DBcAMP increased the GS biological activity only in the cerebral hemisphere cultures. It raised, however, the level of translated GS and GS protein in astrocytes from all the areas, suggesting a post-translational effect for intracellular cAMP. DBcGMP only affected GS in the astrocytes from cerebral hemispheres and the medulla modulating either the GS transcription or the messenger RNA stability. These results suggest specific regulation for GS expression, depending on the brain area from which the cells were dissociated or on the astroglial cell population present in these cultures affecting either the transcription, the mRNA stability, or the biological activity of the protein.
从小鼠大脑半球、小脑、嗅球和延髓分离得到的星形胶质细胞，在激素（氢化可的松、胰岛素）或细胞第二信使（二丁酰环磷腺苷，二丁酰环磷鸟苷）存在的情况下进行培养。研究了在这些因素作用下谷氨酰胺合成酶（GS）的比活性、GS蛋白水平和GS翻译情况。氢化可的松使GS翻译、GS水平和活性同时增加。在从四个脑区培养的星形胶质细胞中均观察到这种增加，但增加幅度因脑区而异。氢化可的松的作用出现在转录水平。相反，胰岛素降低了GS活性和体外翻译的GS。这种作用仅在嗅球和延髓中可见。二丁酰环磷腺苷仅在大脑半球培养物中增加了GS的生物活性。然而，它提高了所有区域星形胶质细胞中翻译的GS和GS蛋白的水平，表明细胞内cAMP具有翻译后效应。二丁酰环磷鸟苷仅影响大脑半球和延髓星形胶质细胞中的GS，调节GS转录或信使核糖核酸稳定性。这些结果表明，GS表达存在特异性调控，这取决于细胞解离的脑区或这些培养物中存在的星形胶质细胞群体，它们会影响转录、信使核糖核酸稳定性或蛋白质的生物活性。
