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A possible new signal trunsduction mechanism of anterior pituitary cells

垂体前叶细胞可能的新信号转导机制

基本信息

批准号：
09660326
负责人：
HASHIMOTO Inoru
金额：
$ 2.11万
依托单位：
Kitasato University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09660326/
关键词：
annexin V prolactin LH gonadotrope anterior pituitary time resolved fluorometric immunoassay paracrine LH beta subunit 組換え蛋白質アネキシン5 下垂体オートクリン

项目摘要

Physiological importance of a novel calcium-phospholipid binding protein, armexin V.in functions of the anterior pituitary gland was investigated. We synthesized recombinant rat annexin V, and purified it by the affinity to phospholipid membranes and the reverse phase HPLC.When annexin V was applied to the primary culture of rat anterior pituitary cells, it dramatically increased LH release but inhibited prolactin release. These diverse effects were driven by different mechanisms. As anti annexin V itself augmented prolactin release and Indomethacin reversed this effect, annexin V was thought to inhibit prolactin release by inhibiting phospholipase A2 and reducing prostaglandin synthesis in the primary culture. Prostaglandins are shown to stimulate prolactin release in vitro. On the other hand, the stimulating effect of annexin V on LH secretion is specific to gonadotropes. By using semi-quantitative RT-PCR, annexin V was also shown to stimulate LH beta subunit synthesis. Hence, annexin V was shown to enhance the all process of LH secretion, namely from synthesis to release. As we had observed annexin V distributed on gonadotropes by immunocytochemistry, we examined whether gonadoiropes themselves could synthesize annexin V.For this purpose, we utilized clonal cell line of the gonadotropes, alphaT3-1, to examine the expression of annexin V mRNA and found this cell line synthesizes annexin V.This result suggests the pituitary gonadotropes synthesize annexin V.Getting together, annexin V is suggested to function as a factor of the signal transduction to enhance the synthesis and the release of LH at the gonadotropes, and it is supposed to work simultaneously as a paracrine factor to inhibit prolactin cell function.

研究了一种新的钙-磷脂结合蛋白armexin对垂体前叶功能的生理学意义V.in我们合成了重组大鼠膜联蛋白V，并通过磷脂膜亲和层析和反相高效液相色谱法对其进行了纯化。将膜联蛋白V应用于原代培养的大鼠垂体前叶细胞，发现膜联蛋白V显著增加LH的释放，但抑制催乳素的释放。这些不同的影响是由不同的机制驱动的。由于抗膜联蛋白V本身增加了催乳素的释放，而吲哚美辛逆转了这种作用，因此膜联蛋白V被认为通过抑制磷脂酶A2和减少原代培养物中前列腺素的合成来抑制催乳素的释放。前列腺素在体外可刺激催乳素的释放。另一方面，膜联蛋白V对LH分泌的刺激作用是促性腺激素特异性的。通过使用半定量RT-PCR，膜联蛋白V也显示刺激LH β亚基合成。因此，膜联蛋白V显示出增强LH分泌的所有过程，即从合成到释放。由于免疫细胞化学观察到膜联蛋白V分布在促性腺激素细胞上，我们检测了促性腺激素本身是否可以合成膜联蛋白V。为此，我们利用促性腺激素细胞克隆系α T3 -1检测膜联蛋白V mRNA的表达，发现该细胞系合成膜联蛋白V。膜联蛋白V被认为是一种信号转导因子，促进促性腺激素细胞LH的合成和释放，同时也被认为是一种旁分泌因子，抑制催乳素细胞功能。