HORSERADISH-PEROXIDASE TRANSPORT ACROSS ADULT-RABBIT JEJUNUM INVITRO
HORSERADISH-PEROXIDASE TRANSPORT ACROSS ADULT-RABBIT JEJUNUM INVITRO
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DOI：
10.1152/ajpgi.1982.242.6.g558
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发表时间：
1982-01-01
影响因子：
--
通讯作者：
MORGAT, JL
中科院分区：
文献类型：
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作者：
HEYMAN, M;DUCROC, R;MORGAT, JL
使用通过成年兔空肠的辣根过氧化物酶（HRP）转运来检查完整蛋白质摄取、代谢行为和跨肠壁传输的定量和功能特征。跨上皮 HRP 通量用改良的 Ussing 装置测定。在林格溶液中，从粘膜到浆膜的完整 HRP 通量之间没有发现显着差异。**图形**。以及从浆膜到粘膜的那些。**图形**。 （分别为 3.12.+-.0.58 和 3.48.+-.0.45 pmol.cntdot.h-1.cntdot.cm-2）。在 10 mM 葡萄糖存在下，注意到轻微的净分泌。转运机制对代谢抑制剂、秋水仙碱和氨敏感。通过测量氚化辣根过氧化物酶 J[3H]HRP 的跨上皮通量来评估细胞内转移和分解代谢。 3H当量HRP (91.+-.32pmol.cntdot.h-1.cntdot.cm-2)的净吸收主要以2-4k道尔顿的氚化降解分解代谢物的形式发生。通过比较完整的和 3H 等效 HRP 的跨上皮通量，可以估计 97% 的 HRP 在从粘膜穿过组织到浆膜时被降解，而在从浆膜穿过到粘膜时则有 88% 被降解。观察到的饱和吸收。**图形**。成为.**GRAPHIC** 的不可饱和过程。这些结果符合至少 2 条肠道蛋白质转运功能途径的存在。主要途径似乎涉及内吞作用，可能在通过溶酶体系统期间发生显着的细胞内降解。逃避代谢降解的 HRP 通过另一种途径运输，需要上皮细胞的结构和代谢完整性。尽管该途径仅占 HRP 转运的一小部分，但它可能具有免疫学重要性。
Quantification and functional characteristics of intact protein uptake, metabolic behavior and transmission across the intestinal wall were examined using horseradish peroxidase (HRP) transport through adult rabbit jejunum. Transepithelial HRP fluxes were determined with a modified Ussing apparatus. In Ringer solution, no significant difference was found between intact HRP fluxes from mucosa to serosa .**GRAPHIC**. and those from serosa to mucosa .**GRAPHIC**. (3.12 .+-. 0.58 and 3.48 .+-. 0.45 pmol.cntdot.h-1.cntdot.cm-2, respectively). In the presence of 10 mM glucose, slight net secretion was noted. The transport mechanism was sensitive to metabolic inhibitors, colchicine and ammonia. Intracellular transfer and catabolism were estimated by measuring transepithelial fluxes of tritiated horseradish peroxidase J[3H]HRP. Net absorption of 3H equivalent HRP (91 .+-. 32 pmol.cntdot.h-1.cntdot.cm-2) occurred chiefly in the form of tritiated degraded catabolites of 2-4 kdaltons. Comparison of the transepithelial fluxes of intact and 3H equivalent HRP made it possible to estimate that 97% of the HRP was degraded while crossing the tissue from mucosa to serosa and 88% while crossing from serosa to mucosa. The saturable absorption observed for .**GRAPHIC**. became a nonsaturable process for .**GRAPHIC**. These results fit the existence of at least 2 functional pathways for intestinal protein transport. The main route seems to involve endocytosis, with striking intracellular degradation, possibly during passage through the lysosomal system. The HRP that escapes metabolic degradation is transported by an alternative route requiring the structural and metabolic integrity of the epithelial cells. Although this route only accounts for a small fraction of HRP transport, it may be of immunological importance.