The effects of maitotoxin on 45Ca2+ flux and hormone release in GH3 rat pituitary cells.
The effects of maitotoxin on 45Ca2+ flux and hormone release in GH3 rat pituitary cells.
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麦毒毒素对 GH3 大鼠垂体细胞 45Ca2 通量和激素释放的影响。
DOI：
10.1210/endo-116-2-622
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发表时间：
1985
期刊：
影响因子：
4.8
通讯作者：
R. Macleod
中科院分区：
文献类型：
--
作者：
I. Login;A. Judd;M. Cronin;K. Koike;G. Schettini;T. Yasumoto;R. Macleod
据报道，麦芽毒素可激活钙通道并刺激多种组织中的钙依赖性功能，但缺乏对 45Ca2+ 通量的彻底研究。为了更详细地表征麦芽毒素对 45Ca2+ 通量的影响，我们将分散的 GH3 垂体肿瘤细胞与麦芽毒素和其他影响钙通道的药物一起孵育在 45Ca2+ 中。在暴露后 10 秒内，麦芽毒素诱导细胞中处于同位素平衡状态的净钙流入。钙吸收在 0.4 至 40 ng/ml 麦芽毒素范围内呈浓度依赖性，并受电压依赖性钙通道拮抗剂抑制，但不受钠通道抑制剂抑制。麦芽毒素在 1 分钟内刺激灌注的 GH3 细胞释放 PRL 和 GH。我们得出的结论是，麦芽毒素通过假定的电压依赖性内源性钙通道导致钙快速、浓度依赖性流入，最终导致激素释放增强。这种强效毒素可以让人们更准确地了解钙在刺激-分泌耦合过程中的作用。
Maitotoxin has been reported to activate calcium channels and stimulate calcium-dependent functions in several tissues, but a thorough investigation of 45Ca2+ fluxes is lacking. To characterize the influence of maitotoxin on 45Ca2+ flux in greater detail, we incubated dispersed GH3 pituitary tumor cells in 45Ca2+ with maitotoxin and other agents affecting calcium channels. Within 10 sec of exposure, maitotoxin induced a net calcium influx in cells at isotopic equilibrium. Calcium uptake was concentration dependent between 0.4 and 40 ng/ml maitotoxin and was inhibited by antagonists of voltage-dependent calcium channels but not by inhibitors of sodium channels. PRL and GH release from perifused GH3 cells was stimulated within 1 min by maitotoxin. We conclude that maitotoxin causes a rapid, concentration-dependent influx of calcium through presumed voltage-dependent endogenous calcium channels, culminating in enhanced hormone release. This potent toxin may provide a more precise understanding of the role of calcium in the stimulus-secretion coupling process.
影响因子：
4.1
作者：
THORNER, MO;HACKETT, JT;MACLEOD, RM
通讯作者：
MACLEOD, RM