Synthesis of cyclic peptides containing His and its possibility of brain activating

在哺乳动物大脑的下丘脑中合成的垂体激素释放激素现在被称为TRH，LHRH，CRH，GHRH等等。其中，低分子量肽、TRH和LHRH在结构上具有相似性。这两种肽的n端氨基酸均为焦谷氨酸，c端氨基酸为His和氨基酸酰胺。我们已经明确了大鼠脑内存在焦氨酰肽酶，该酶能产生环状肽；histidyl-proline二酮哌嗪。这种环状肽被认为是一种激活大脑的物质。释放激素的生物活性表现出多种功能，包括脑激活能力，可能与环肽有关。在这种情况下，我们合成了四种含有His的肽，然后成功地制备了针对每个环肽具有特异性的抗体。利用这些抗体，我们想要发展能够清除大脑中肽分布的微测定和免疫组织化学方法。除此之外，我们还想通过垂体细胞培养和western blotting方法了解环肽释放垂体激素的能力。两年对这个项目来说是不够的。我们现在需要更多的时间，而环肽作为大脑激活物质的可能性需要在动物体内进行实验。这个项目最初是4个成员计划的，但有2个成员被调离，无法加入这个项目。只有两个成员开始这个项目（后来另一个加入）。所以，我们现在要抓紧时间。

Pitutitary hormone-releasing hormones which are synthesized in the hypothalamus of the mammalian brain are now known as TRH,LHRH,CRH,GHRH,and so on. Among them, low molecular weight peptides, TRH and LHRH show the structural similarities. Both peptides have pyroGlu as N-terminal amino acid, His, and amino acid amide as C-terminal. We have already cleared that there is pyrogrutamyl peptidase in rat brain and the protease makes cyclic peptide ; histidyl-proline diketopiperazine. This cyclic peptide is supposed to behave as a brain activating substance. Biological activities of the releasing-hormones which show many functions including brain activating ability might be due to the cyclic peptides.Under the circumstances we synthesized four peptides which contain His, then succeeded in making antibodies which have specificities against each cyclic peptide. Using the antibodies we wanted to develop the microdetermination and immunohistochemical methods which can clear the peptide distribution in the brain. Besides those, using pituitary cell culture and western blotting methods, we wanted to know the pituitary hormonereleasing abilities of cyclic peptides. Two years was not enough for this project. We now need more time, and the possibility of cyclic peptides as brain activating substances needs the experiments using animals in vivo.This project was planned among 4 members at first, but two members were tranferred and were not able to join this project. Only 2 members started this project (afterwards another joined). So, we now making haste.