Weber E, Lorenzoni P, Raffaelli N, Cavina N, Sacchi G
Istituto di Anatomia Umana Normale, University of Siena, Italy.
Biochem Biophys Res Commun. 1996 Aug 23;225(3):1040-4. doi: 10.1006/bbrc.1996.1291.
Glial cells have been shown to induce enzyme activities, which are characteristically high in brain capillaries, in cerebral and non cerebral endothelial cells in culture. We evaluated the activity of gamma-glutamyl transpeptidase (gamma GT) in freshly isolated (ex vivo) bovine blood (BEC) and lymphatic (LEC) endothelial cells. We also tested the effect of C6 glioma cell conditioned medium (GCM) on gamma GT activity of BEC and LEC in primary culture. Ex vivo BEC had a high gamma GT activity, only 9% of which was retained in culture. After exposure to GCM, however, gamma GT activity of cultured BEC was twofold higher than with control medium. By contrast gamma GT activity was extremely low in ex vivo LEC and did not significantly increase in cultured LEC exposed to GCM. These data show that the basal levels of gamma GT are markedly different in BEC and LEC and also that, unlike BEC, LEC are not capable of producing more gamma GT in response to glial stimulation.
已表明神经胶质细胞可诱导培养的脑和非脑内皮细胞中的酶活性，这些酶活性在脑毛细血管中通常较高。我们评估了新鲜分离的（体外）牛脑内皮细胞（BEC）和淋巴管内皮细胞（LEC）中γ-谷氨酰转肽酶（γGT）的活性。我们还测试了C6胶质瘤细胞条件培养基（GCM）对原代培养的BEC和LEC的γGT活性的影响。体外BEC具有较高的γGT活性，其中只有9%在培养中得以保留。然而，在暴露于GCM后，培养的BEC的γGT活性比对照培养基高出两倍。相比之下，体外LEC中的γGT活性极低，并且在暴露于GCM的培养LEC中没有显著增加。这些数据表明，BEC和LEC中γGT的基础水平明显不同，而且与BEC不同，LEC不能响应神经胶质细胞刺激而产生更多的γGT。
