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.
|ジャーナル||Pharmaceutical Research: An Official Journal of the American Association of Pharmaceutical Scientists|
|出版ステータス||Published - 1992 4|
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