Fukuta M, Okada H, Iinuma S, Yanai S, Toguchi H
DDS Research Laboratories, Takeda Chemical Industries, Ltd., Osaka, Japan.
Pharm Res. 1994 Dec;11(12):1681-8. doi: 10.1023/a:1018942728317.
The possibility of using insulin (INS), which is transported into the brain by receptor-mediated transcytosis, as a peptide carrier for delivery across the blood-brain barrier (BBB) was investigated. After mice received an i.v. injection of horseradish peroxidase (HRP, M.W., 40,000) conjugated with INS, the HRP activity in the brain was higher than that after HRP injection. Since INS-HRP lowered the blood glucose level, we prepared insulin fragments by chemical and enzymatic procedures in an effort to find a carrier with no hypoglycemic activity. Seven fragments were synthesized taking the binding regions into consideration, but none showed any receptor binding affinity in cultures of bovine brain microvessel endothelial cells (BMEC). However, the fragment (F007) obtained by trypsin digestion showed high affinity and scarcely any hypoglycemic activity in mice even at a dose ten times the effective dose of insulin. These results suggest that this fragment may be useful as a carrier to transport therapeutic peptides across the BBB.
研究了利用胰岛素（INS）作为肽载体跨越血脑屏障（BBB）进行递送的可能性，胰岛素可通过受体介导的转胞吞作用进入大脑。小鼠静脉注射与INS偶联的辣根过氧化物酶（HRP，分子量40,000）后，大脑中的HRP活性高于注射HRP后的活性。由于INS-HRP降低了血糖水平，我们通过化学和酶促方法制备了胰岛素片段，试图找到一种无降血糖活性的载体。考虑到结合区域合成了七个片段，但在牛脑微血管内皮细胞（BMEC）培养物中，没有一个显示出任何受体结合亲和力。然而，通过胰蛋白酶消化获得的片段（F007）在小鼠中显示出高亲和力，即使剂量是胰岛素有效剂量的十倍，也几乎没有降血糖活性。这些结果表明，该片段可能作为一种载体，用于将治疗性肽转运穿过血脑屏障。
