Insulin induces Ca2+ influx into isolated rat hepatocyte couplets
Insulin induces Ca2+ influx into isolated rat hepatocyte couplets
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DOI：
10.1152/ajpgi.1997.272.6.g1425
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发表时间：
1997-06-01
影响因子：
4.5
通讯作者：
Haddad, P
中科院分区：
文献类型：
--
作者：
Benzeroual, K;VandeWerve, G;Haddad, P
用离体大鼠肝细胞偶联研究胰岛素对细胞内Ca ~（2+）稳态的直接影响。胰岛素诱导肝细胞Ca 2+呈剂量依赖性增加，这种增加是渐进的，通常是双相的，并且是可逆的。细胞外Ca 2+的螯合消除了胰岛素诱导的Ca 2+反应，并且这种抑制与对胰岛素结合的影响无关，如置换研究所示。因此，我们测试了几种Ca 2+通道抑制剂对胰岛素诱导的Ca 2+内流的影响。维拉帕米在20或200 μ M没有效果，而500 μ M镍和50 μ M钆强烈抑制胰岛素诱导的Ca 2+进入。最后，我们测试了胰岛素诱导的Ca 2+运动是否与促分裂原活化蛋白激酶（MAPK）活性的刺激有关，我们使用免疫复合物测定法测定了MAPK活性。维拉帕米对p44（mapk）活性的胰岛素依赖性刺激没有影响，而加入乙二醇-双（β-氨基乙基醚）-N，N，N '，N'-四乙酸、镍或钆强烈抑制肽激素的作用。我们的研究结果表明，胰岛素触发Ca 2+流入肝细胞，可能是通过打开质膜上的通道，这种效果是重要的胰岛素激活MAPK。
Isolated rat hepatocyte couplets were used to study the direct effect of insulin on intracellular Ca2+ homeostasis. Insulin induced a dose-dependent increase in hepatocellular Ca2+ that was gradual, generally monophasic, and reversible. Chelation of extracellular Ca2+ abolished the insulin-induced Ca2+ response, and this suppression was not related to an effect on insulin binding, as indicated by displacement studies. We thus tested the effect of several Ca2+ channel inhibitors on insulin-induced Ca2+ influx. Verapamil at 20 or 200 mu M was without effect, whereas 500 mu M nickel and 50 mu M gadolinium strongly inhibited insulin-induced Ca2+ entry. Finally, we tested whether insulin-induced Ca2+ movements were implicated in the stimulation of mitogen-activated protein kinase (MAPK) activity, which we measured with the use of an immune-complex assay. Verapamil was without effect on the insulin-dependent stimulation of p44(mapk) activity, whereas addition of ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid, nickel, or gadolinium strongly inhibited the effect of the peptide hormone. Our results indicate that insulin triggers Ca2+ influx into hepatocytes, possibly through the opening of channels on the plasma membrane, and that this effect is important for insulin activation of MAPK.