Insulin-like growth factor-I-enhanced secretion is abolished in protein kinase C-deficient chromaffin cells.
Insulin-like growth factor-I-enhanced secretion is abolished in protein kinase C-deficient chromaffin cells.
复制标题
在蛋白激酶 C 缺陷的嗜铬细胞中，胰岛素样生长因子 I 增强的分泌被消除。
DOI：
10.1046/j.1471-4159.1994.62051707.x
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发表时间：
1994
影响因子：
4.7
通讯作者：
Dahmer,MK
中科院分区：
文献类型：
--
作者：
Penberthy,WT;Dahmer,MK
先前的研究表明，在含有 10 nMinsulin 样生长因子-I (IGF-I) 的培养基中培养的牛嗜铬细胞在受到分泌刺激时，所分泌的儿茶酚胺是不含 IGF-I 的细胞的两倍。本研究的目的是确定蛋白激酶 C (PKC) 是否参与 IGF-I 对这些细胞分泌的影响。用 β-佛波醇二癸酸酯（β-PDD；100 nM）处理 16-18 小时后，细胞中的 PKC 下调。这种处理对无 IGF-I 培养的细胞的高 K+ 刺激分泌没有影响；然而，用 IGF-I 培养的细胞的分泌量降低到与不含肽培养的细胞相当的水平。无活性异构体 α-PDD (100 nM) 对未经处理或 IGF-I 处理的嗜铬细胞的分泌没有影响。 β-PDD 的作用具有时间和浓度依赖性，100 nM β-PDD 在 8-10 小时内产生最大作用。在用 PMA (300 nM) 处理的透化细胞中测量的原位 PKC 活性在 10 小时内降低约 40%，并在 18 小时内降低至几乎基础水平。免疫印迹实验表明，α-和 ε-PKC 从细胞中丢失，其时间过程与原位 PKC 测定中观察到的时间过程相似。 PKC 抑制剂 H7 (100 μM) 过夜处理可防止 IGF-1 处理细胞中通常出现的分泌增强，而 HA1004 则没有效果。长期使用 β-PDD (200 nM) 或 H7 (100 μM) 治疗会减弱 IGF-I 处理细胞中高 K+ 刺激的 45Ca2+ 摄取。这些观察结果表明 PKC 是嗜铬细胞 IGF-I 增强分泌所必需的。
Previous studies have demonstrated that bovine chromaffin cells cultured in medium with 10 nMinsulin‐like growth factor‐I (IGF‐I) secrete about twofold more catecholamine when exposed to secretory stimuli than do cells cultured without IGF‐I. The purpose of this study was to determine whether protein kinase C (PKC) is involved in the effect of IGF‐I on secretion from these cells. PKC was down‐regulated in the cells by 16–18 h of treatment with β‐phorbol didecanoate (β‐PDD; 100 nM). Such treatment had no effect on high‐K+‐stimulated secretion from cells cultured without IGF‐I; however, secretion from cells cultured with IGF‐I was reduced to a level comparable to that in cells cultured without the peptide. The inactive isomer, α‐PDD (100 nM), had no effect on secretion from untreated or IGF‐I‐treated chromaffin cells. The effect of β‐PDD was time and concentration dependent, with 100 nM β‐PDDproducing a maximal effect in 8–10 h. In situ PKC activity measured in permeabilized cells treated with PMA (300 nM) was decreased by∼40% by 10 h and was reduced to almost basal levels by 18 h. Immunoblotting experiments demonstrated that both α‐and ε‐PKC were lost from the cells with time courses similar to that seen in the in situ PKC assay. Overnight treatment with the PKC inhibitor H7 (100 μM) prevented the enhanced secretion normally seen in IGF‐l‐treated cells, whereas HA1004 had no effect. High‐K+‐stimulated45Ca2+uptake in IGF‐I‐treated cells was attenuated by long‐term treatment with β‐PDD (200 nM) or H7 (100 μM). Together these observations suggest that PKC is required for IGF‐I‐enhanced secretion from chromaffin cells.