Regulation of hexose carriers in chicken embryo fibroblasts. Effect of glucose starvation and role of protein synthesis.
Regulation of hexose carriers in chicken embryo fibroblasts. Effect of glucose starvation and role of protein synthesis.
复制标题
鸡胚成纤维细胞中己糖载体的调节。
DOI：
10.1016/s0021-9258(17)44567-4
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发表时间：
1983
期刊：
影响因子：
--
通讯作者：
K. Isselbacher
中科院分区：
文献类型：
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作者：
K. Yamada;L. Tillotson;K. Isselbacher
研究了鸡胚成纤维细胞（CEF）在葡萄糖饥饿期间己糖转运活性增强4- 8倍的己糖转运调节。放线菌酮在低浓度（0.5微克/毫升）在饥饿期间的存在下，在很大程度上阻止了运输活动的增强。在饥饿状态下，CEF的葡萄糖再喂养导致运输下降到基础水平。这种下降是加强或封锁的放线菌酮的存在下，在低或高（50微克/毫升）浓度，分别。暴露CEF在饲料状态下低浓度的放线菌酮导致在6小时内运输减少70%，而暴露于高浓度的放线菌酮导致只有适度的损失（减少35%）。在葡萄糖饥饿状态下，无论是高浓度还是低浓度的放线菌酮，CEF的转运都没有明显下降。3-O-甲基葡萄糖的摄取由美联储，饥饿，或环己酰亚胺处理的CEF密切相关的D-葡萄糖转运活性和[3 H]细胞松弛素B结合从CEF暴露在相同的条件下制备的质膜。CEF的己糖转运活性似乎在很大程度上取决于质膜上功能载体的数量，这显然反映了载体合成和失活之间的平衡。这两个过程需要蛋白质合成，但对放线菌酮的影响不同敏感，因此低浓度的放线菌酮似乎主要阻断合成，而高浓度则阻断两个过程。此外，在饥饿过程中，运输的增强似乎主要是由于载体失活减少，面对持续的载体合成。
Regulation of hexose transport was investigated in chicken embryo fibroblasts (CEF) which develop 4- to 8-fold enhanced hexose transport activity during glucose starvation. The presence of cycloheximide in low (0.5 micrograms/ml) concentrations during starvation largely blocked the enhancement of transport activity. Glucose refeeding of CEF in the starvation state led to a decline in transport to the basal level. This decline was either potentiated or blocked by the presence of cycloheximide in low or high (50 micrograms/ml) concentrations, respectively. Exposure of CEF in the fed state to low concentrations of cycloheximide resulted in a 70% decrease of transport within 6 h, whereas exposure to high concentrations of cycloheximide led to only a modest loss (35% decrease). In the glucose-starved state, CEF had no significant decline of transport when exposed to cycloheximide at either high or low concentrations. The uptake of 3-O-methylglucose by fed, starved, or cycloheximide-treated CEF correlated closely with D-glucose transport activity and [3H]cytochalasin B binding by plasma membranes prepared from CEF exposed to the same conditions. Hexose transport activity of CEF seems to largely depend on the number of functioning carriers in the plasma membrane, which apparently reflect the balance between carrier synthesis and inactivation. These two processes require protein synthesis, but are differentially sensitive to the effects of cycloheximide, such that low concentrations of cycloheximide appear to block primarily synthesis while high concentrations block both processes. Furthermore, during starvation the enhancement of transport appears largely due to decreased carrier inactivation in the face of continued carrier synthesis.