Flögel U, Leibfritz D
Institut für Organische Chemie, Universität Bremen, Germany.
Neurochem Res. 1998 Dec;23(12):1553-61. doi: 10.1023/a:1020984105448.
NMR spectroscopy of F98 glioma cell extracts showed that chronic hypertonic conditions largely increased the intracellular content of small, osmotically active molecules. Moreover, hypertonic stress decreased the incorporation of 13C-labeled amino acids into the cellular proteins albeit their cytosolic concentrations were increased, which reflects an inhibition of protein synthesis under these conditions. Reincubation with isotonic medium restored almost completely the control values for the cytosolic metabolites but not for amino acid incorporation into the protein. An increased amount of 13C label was found in the phospholipids, which indicates stimulation of membrane synthesis processes due to the recovery-induced cell swelling. On the other hand, chronic hypotonic conditions largely decreased the steady state concentration and synthesis of small, cytosolic molecules, whereas the effect on the incorporation of 13C-labeled amino acids into the cellular proteins was variable. Reincubation with isotonic medium partially restored the depressed cytosolic metabolite content and also the incorporation of labeled amino acids into cellular protein, but induced an inhibition of phospholipid synthesis. The results verify that 'readaptation' of glial cell metabolism during recovery from chronic osmotic stress is impaired or at least seriously retarded.
对F98胶质瘤细胞提取物进行的核磁共振光谱分析表明，长期高渗条件下，细胞内小分子渗透活性物质的含量大幅增加。此外，尽管细胞溶质中13C标记氨基酸的浓度有所增加，但高渗应激仍降低了其掺入细胞蛋白质的量，这反映出在此条件下蛋白质合成受到抑制。用等渗培养基再孵育后，细胞溶质代谢物的对照值几乎完全恢复，但氨基酸掺入蛋白质的情况并未恢复。在磷脂中发现13C标记量增加，这表明恢复诱导的细胞肿胀刺激了膜合成过程。另一方面，长期低渗条件下，细胞溶质中小分子的稳态浓度和合成大幅降低，而对13C标记氨基酸掺入细胞蛋白质的影响则各不相同。用等渗培养基再孵育可部分恢复降低的细胞溶质代谢物含量以及标记氨基酸掺入细胞蛋白质的情况，但会抑制磷脂合成。结果证实，胶质细胞在从慢性渗透应激恢复过程中的代谢“再适应”受损或至少严重受阻。
