HORMONE REGULATION OF CA2+ IN PANCREATIC ACINAR CELLS

这个项目的主要目的是扩大我们对 Ca ~（2+）动员激素对Ca ~（2+）渗透性的影响， 胰腺腺泡细胞胞内钙泵。 这是理解这一问题的重要阶段。 细胞内储存的释放和再装载机制 用Ca 2+厄普顿细胞刺激和去除刺激。 到目前为止， 我们已经开发了技术，以测量游离胞质Ca 2+， 使用Ca 2+敏感染料FURA的完整胰腺腺泡细胞 2;特异性标记激素可动员的细胞内池 用完整细胞中的45 Ca;测量Ca 2+通道介导的- 完整和透化细胞中的45 Ca通量;并测量 Ca ~（2+）泵介导透性化细胞~（45）Ca流动。 使用 这些技术，直接的目的是（a）演示， 从细胞内池释放的Ca 2+足以激活 质膜钙通道。 这个频道的激活是 不直接介导，不需要存在 激素. (b)表明激素，如IP 3，激活Ca 2 + 内质网膜上的一个通道。 (c)比较 IP 3、GTP和花生四烯酸对激素的影响 激活细胞内钙释放。 (d)研究 IP 3、GTP和花生四烯酸对激素的贡献 依赖性Ca 2+释放（e）定义了新的 发现，激活内质网钙泵 通过Ca 2+动员激素（f）试图表征 内质网钙泵激活机制 通过Ca 2+泵和Ca 2+动员激素。 我们的基础研究提供了技术来测试假设， 细胞内游离Ca ~（2+）和Ca ~（2+）含量激素调节 胰腺腺泡细胞的细胞内储存， 在细胞刺激终止时。

The principal object of this project is to extend our studies on the effect of Ca2+ mobilizing hormones on the Ca2+ permeability and Ca2+ pump of the intracellular stores of pancreatic acinar cells. This constitutes as essential stage towards understanding the mechanisms of release and reloading of the intracellular stores with Ca2+upton cell stimulation and removal of stimuli. To date, we have developed techniques; to measure free cytosolic Ca2+ in intact pancreatic acinar cells using the Ca2+ sensitive dye FURA 2; to specifically label the hormone mobilizable intracellular pool with 45Ca in intact cells; to measure Ca2+ channel mediated - 45Ca fluxes in intact and permeabilized cells; and to measure Ca2+ pump mediated -45Ca fluxes in permeabilized cells. Using these techniques, the immediate aims are (a) demonstration that Ca2+ release from the intracellular pool is sufficient to activate the plasma membrane Ca2+ channel. Activation of this channel is not directly mediated and does not require the presence of the hormone. (b) Show that the hormone, like IP3, activates a Ca2+ channel in the endoplasmic reticulum membrane. (c) Compare the effects of IP3, GTP and arachidonic acid with the hormone activated Ca2+ release from the intracellular pool. (d) Study the contribution of IP3, GTP and arachidonic acid to the hormone dependent Ca2+ release (e) define the requirements for the newly discovered, activation of the endoplasmic reticulum Ca2+ pump by the Ca2+ mobilizing hormone (f) attempt to characterize the mechanism of activation of the endoplasmic reticulum Ca2+ pump by the Ca2+ pump by the Ca2+ mobilizing hormones. Our basic studies are providing techniques to test hypotheses on hormonal regulation of free cytosolic Ca2+ and Ca2+ content in the intracellular stores of pancreatic acinar cells both during and at the termination of cell stimulation.