Physiological Roles of a Novel Calcium Phospholipid Binding Protein, Annexin V,in the Function of the Anterior Pituitary Gland and the Ovary ; A Molecular-Cellular Biological Approach

研究了一种新的钙磷脂结合蛋白膜联蛋白V在垂体前叶和卵巢功能中的生理重要性。用免疫细胞化学方法，证实了膜联蛋白V在垂体前叶促性腺激素细胞上的特异性分布。卵巢切除后，垂体前叶中这种蛋白质的含量增加。北方印迹分析也显示卵巢切除增强膜联蛋白V的合成。这些结果使我们研究GnRH对膜联蛋白V合成的影响，我们发现GnRH对膜联蛋白V mRNA积累的刺激作用。反过来，膜联蛋白V增加LH β mRNA。结合起来，膜联蛋白V被认为是一种新的信号转导的GnRH在垂体促性腺激素细胞。膜联蛋白V被假设为也是卵巢的生理调节剂。膜联蛋白V的分布仅限于黄体细胞。颗粒细胞既不显示膜联蛋白V，也不显示其mRNA。此外，黄体膜联蛋白V的浓度沿着假孕而变化。这些结果表明膜联蛋白V在黄体促孕功能中发挥作用。我们还观察了annexin V对离体下丘脑单单位活动（SUA）的影响。尽管我们只有初步的数据，膜联蛋白V显示出抑制或刺激显着的神经放电活动。本项目的生理作用的膜联蛋白V提出了一种可能性，膜联蛋白V发挥特定的活动，局部在各种组织。其中，对促性腺激素细胞的信号转导作用是首次观察到其生理调节活性。

Physiological importance of a novel calcium-phospholipid binding protein, annexin V,in functions of the anterior pituitary gland and the ovary was investigated. By immunocytochemical approach, the specific distribution of annexin V on gonadotrophs at the anterior pituitary gland was demonstrated. The amount of this protein in the anterior pituitary gland was revealed to increase after ovariectomy. It was shown that ovariectomy enhances annexin V synthesis also by Northern blot analysis. These results led us to examine the effect of GnRH on annexin V synthesis and we found a stimulating effect of GnRH on annexin V mRNA accumulation. In turn, annexin V increased LH beta mRNA.Getting together, annexin V is thought to be a novel signal transducer of GnRH at pituitary gonadotrophs. Annexin V is hypothesized to be a physiological modulator also at the ovary. The distribution of annexin V was shown to restricted to luteal cells. Granulosa cells showed neither annexin V nor its mRNA.Furthermore, luteal annexin V varies its concentration along with pseudopregnancy. These results suggest annexin V would play a role in luteal progestational function. We also examined the effect of annexin V in neural system by observing single unit activity (SUA) recorded with a section of hypothalamus in vitro. Even though we have only preliminary data, annexin V was shown to inhibit or stimulate significantly the neural firing activity. The present project on the physiological role of annexin V raises a possibility that annexin V exerts specific activity locally in various tissues. Among these, its signal transducing action at gonadotrophs is the first observation on its activity of physiological modulator.