Transport mechanism of a new behaviorally highly potent adrenocorticotropic hormone (ACTH) analog, ebiratide, through the blood-brain barrier.
Transport mechanism of a new behaviorally highly potent adrenocorticotropic hormone (ACTH) analog, ebiratide, through the blood-brain barrier.
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一种新型行为高效促肾上腺皮质激素 (ACTH) 类似物依比拉肽穿过血脑屏障的转运机制。
DOI：
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发表时间：
1991
影响因子：
3.5
通讯作者：
Akira Tsuji
中科院分区：
文献类型：
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作者：
T. Shimura;Shigeru Tabata;T. Ohnishi;Tetsuya Terasaki;Akira Tsuji
本文研究了一种新的促肾上腺皮质激素（ACTH）类似物依必拉特（H-Met（O_2）-Glu-His-Phe-D-Lys-Phe-NH（CH_2）_8NH_2）与牛脑毛细血管的结合和内化。[5- 125 I-His]依必肽的代谢发生在37 ℃下与牛脑毛细血管孵育30分钟期间。在加入20 mM EDTA以抑制该代谢的情况下，孵育30分钟后，培养基中含有82.3 +/- 0.5%的未改变的依比拉肽。[125 I]依比拉肽的总结合和耐酸结合随时间增加，并在约15 min时达到平衡。30 min时的总结合和耐酸结合（用[14 C]蔗糖校正的细胞/培养基比）分别为13.07 +/- 0.86和5.00 +/- 0.18 μ L/mg蛋白。耐酸结合显示出显着的温度和介质渗透压的依赖性。内吞抑制剂丹磺尸胺可显著抑制[125 I]依必肽结合。通过加入未标记的依必肽（100 nM-5 mM）获得可饱和的耐酸结合，30 min时的最大内化能力（Bmax）为144.2 pmol/mg蛋白质，半饱和常数（KD）为62.1 μ M。不饱和耐酸结合[在未标记化合物（1 mM或更高）存在下的细胞/培养基比]为2.2微升/mg蛋白质。抗酸结合显着抑制人促肾上腺皮质激素，聚-L-赖氨酸，鱼精蛋白和E-2078，一种碱性肽，但不抑制聚-L-谷氨酸，胰岛素或转铁蛋白。这些结果表明，依必肽通过碱性肽特异性吸收介导的内吞作用转运通过血脑屏障。
The binding and internalization of a novel adrenocorticotropic hormone (ACTH) analog having a potent neuromodulating effect, ebiratide (H-Met(O2)-Glu-His-Phe-D-Lys-Phe-NH(CH2)8NH2), by isolated bovine brain capillaries, were examined. Metabolism of [5-125I-His]ebiratide occurred during a 30-min incubation with bovine brain capillaries at 37 degrees C. In the presence of 20 mM EDTA, added to inhibit this metabolism, the medium, after 30 min of incubation, contained 82.3 +/- 0.5% of the unchanged ebiratide. The total binding and acid-resistant binding of [125I]ebiratide increased with time and reached an equilibrium at about 15 min. The total binding and acid-resistant binding at 30 min (as the cell/medium ratios corrected with [14C]sucrose) were 13.07 +/- 0.86 and 5.00 +/- 0.18 microliters/mg of protein, respectively. The acid-resistant binding showed significant dependence on temperature and medium osmolarity. The [125I]ebiratide binding was significantly inhibited by dansylcadaverine, an endocytosis inhibitor. The saturable acid-resistant binding was obtained by the addition of unlabeled ebiratide (100 nM-5 mM), and the maximal internalization capacity (Bmax) at 30 min was 144.2 pmol/mg of protein, with the half-saturation constant (KD) of 62.1 microM. The nonsaturable acid-resistant binding [cell/medium ratio in the presence of the unlabeled compound (1 mM or more)] was 2.2 microliters/mg of protein. The acid-resistant binding was significantly inhibited by human ACTH, poly-L-lysine, protamine and E-2078, a basic peptide, but was not inhibited by poly-L-glutamate, insulin or transferrin. These results demonstrate that ebiratide is transported through the blood-brain barrier via a basic peptide-specific absorptive-mediated endocytosis.