Role of insulin and insulin-like growth factor receptors in regulation of T84 cell monolayer permeability.
Role of insulin and insulin-like growth factor receptors in regulation of T84 cell monolayer permeability.
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胰岛素和胰岛素样生长因子受体在调节 T84 细胞单层通透性中的作用。
DOI：
10.1152/ajpgi.1994.267.5.g883
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发表时间：
1994
期刊：
影响因子：
--
通讯作者：
Riley,NE
中科院分区：
文献类型：
--
作者：
McRoberts,JA;Riley,NE
我们以前表明，胰岛素和胰岛素样生长因子（IGF）-I和IGF-II引起剂量依赖性增加的渗透性通过细胞旁途径的T84细胞单层超过3-4天。在这里，我们已经确定了哪些细胞表面受体参与了这种反应。利用放射性配体结合研究和受体交联研究，我们发现T84细胞具有胰岛素和IGF-I受体。约有20 × 10（3）胰岛素受体/细胞，解离常数（KD）为0.5 nM，IGF-I受体约有29 × 10（3）IGF-I受体，解离常数（KD）为0.6 nM。交联研究鉴定了胰岛素和IGF-I受体的α-亚基，推导的分子量分别为126 × 10（3）和128 × 10（3）。IGF-II与T84细胞结合的表观KD约为2.0 nM。放射性受体交联表明，IGF-II主要与IGF-I受体相互作用，虽然低水平的IGF-II/甘露糖6-磷酸受体也表达在细胞表面上。然后，我们将生物学效应与放射性配体结合研究相关联。首次证明胰岛素和IGF-I在细胞存在下在培养基中降解。此外，我们发现，连续暴露于胰岛素或IGF-I 2-3天是产生其对渗透性的生物学效应所必需的。考虑到降解速率和持续暴露的要求，我们发现放射性配体结合与激素对跨上皮渗透性影响的半最大有效浓度之间存在密切相关性。（250字处删节）
We previously showed that insulin and insulin-like growth factor (IGF)-I and IGF-II caused a dose-dependent increase in permeability through the paracellular pathway of T84 cell monolayers over 3-4 days. Here we have determined which cell surface receptors were involved in this response. Using radioligand binding studies and receptor cross-linking studies, we found that T84 cells possess insulin and IGF-I receptors. There were approximately 20 x 10(3) insulin receptors/cell with a dissociation constant (KD) of 0.5 nM and 29 x 10(3) IGF-I receptors with a KD of 0.6 nM for IGF-I. Cross-linking studies identified the alpha-subunit of insulin and IGF-I receptors with deduced molecular weights of 126 x 10(3) and 128 x 10(3), respectively. IGF-II bound to T84 cells with an apparent KD of approximately 2.0 nM. Radioreceptor cross-linking indicated that IGF-II interacted principally with the IGF-I receptor, although low levels of the IGF-II/mannose 6-phosphate receptor were also expressed on the cell surface. We then correlated the biological effect with the radioligand binding studies. It was first demonstrated that insulin and IGF-I were degraded in medium in the presence of cells. In addition, we showed that continuous exposure for 2-3 days to insulin or IGF-I was required to produce their biological effect on permeability. Taking into account the rate of degradation and the requirement for continuous exposure, we found a close correlation between radioligand binding and the half-maximal effective concentration for the hormonal effects on transepithelial permeability.(ABSTRACT TRUNCATED AT 250 WORDS)