Absorptive-Mediated Endocytosis of an Adrenocorticotropic Hormone (ACTH) Analogue, Ebiratide, into the Blood–Brain Barrier: Studies with Monolayers of Primary Cultured Bovine Brain Capillary Endothelial Cells

Tetsuya Terasaki, Susumu Takakuwa, Akira Saheki, Shuzo Moritani, Takesada Shimura, Shigeru Tabata, Akira Tsuji

Research output: Contribution to journalArticle

46 Citations (Scopus)

Abstract

The internalization of a neuromodulatory adrenocorticotropic hormone (ACTH) analogue, [125I]ebiratide (H-Met(O2)-Glu[125I]His-Phe-D-Lys-Phe-NH(CH2)8NH2), was examined in cultured mono-layers of bovine brain capillary endothelial cells (BCEC). HPLC analysis of the incubation solution showed that [125I]ebiratide was not metabolized during the incubation with BCEC. The acid-resistant binding of [125I]ebiratide to BCEC increased with time for 120 min and showed a significant dependence on temperature and medium osmolarity. Pretreatment of BCEC with dansylcadaverine or phenylarsine oxide, endocytosis inhibitors, and 2,4-dinitrophenol, a metabolic inhibitor, decreased significantly the acid-resistant binding of [125I]ebiratide. The acid-resistant binding of [125I]ebiratide was saturable in the presence of unlabeled ebiratide (100 n M–1 m M). The maximal internalization capacity (Bmax) at 30 min was 7.96 ± 3.27 µmol/mg of protein with a half-saturation constant (Kd) of 15.9 ± 6.4 µM. The acid-resistant binding was inhibited by basic peptides such as poly-L-lysine, protamine, histone, and ACTH but was not inhibited by poly-L-glutamic acid, insulin, or transferrin. These results confirmed that ebiratide is transported through the blood-brain barrier via an absorptive-mediated endocytosis.

Original languageEnglish
Pages (from-to)529-534
Number of pages6
JournalPharmaceutical Research: An Official Journal of the American Association of Pharmaceutical Scientists
Volume9
Issue number4
DOIs
Publication statusPublished - 1992 Apr
Externally publishedYes

Keywords

  • absorptive-mediated endocytosis
  • adrenocorticotropic hormone analogue
  • adsorptive endocytosis
  • blood–brain barrier (BBB) transport
  • ebiratide
  • internalization
  • peptide
  • primary cultured brain capillary endothelial cells

ASJC Scopus subject areas

  • Biotechnology
  • Molecular Medicine
  • Pharmacology
  • Pharmaceutical Science
  • Organic Chemistry
  • Pharmacology (medical)

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